The Malagasy Fauna of Strumigenys Author Fisher, Brian L. 1957 - The Malagasy Fauna of Strumigenys Brian L. Fisher Department of Entomology, California Academy of Sciences, 875 Howard Street, San Francisco, California 94103 USA; bfisher@calacademy.org In the most recent synoptic list of the Malagasy fauna (Fisher, 1997) only four species of Strumigenys are recorded. One of these, emmae, is a pantropical tramp species. Another, godeffroyi, is based on an old record that is almost certainly a misidentification as no other material correctly referable to the species has ever been discovered in the region. The final two species of Fisher’s list, grandidieri and scotti, therefore represent the only endemic Malagasy species of this genus that have been described to the present day. This, the first synthesizing taxonomic study of the regional fauna, raises the number of Malagasy species to 75. There are two tramp species, rogeri and emmae, which are listed and keyed here but discussed under the regional faunas of their origin, the Afrotropical and Austral regions respectively. The two other previously described species (grandidieri, scotti) and 71 new species are discussed below. The fauna falls into nine indigenous species groups of which four, containing a total of 19 species, are endemic to Madagascar (apios-group, dexis-group, grandidieri-group and adsita-group). Two species groups, each with only a single species in the Malagasy region, are of Oriental-Malesian origin and are highly speciose in those regions (godeffroyi-group and koningsbergeri-group). The final three groups, containing 53 species, are the most speciose in the Malagasy region and are shared with the Afrotropical region (arnoldi-group, rogeri-group and scotti-group); one of the rogeri-group species, vazimba, is the largest Strumigenys species known. CHECK-LIST OF MALAGASY STRUMIGENYS SPECIES adsita-group 1 species adsita sp. n. apios-group 2 species agra sp. n. apios sp. n. arnoldi-group 13 species abdera sp. n. alapa sp. n. bathron sp. n. charino sp. n. dolabra sp. n. heliani sp. n. levana sp. n. lutron sp. n. manga sp. n. micrans sp. n. mola sp. n. schuetzi sp. n. toma sp. n. dexis-group 9 species alperti sp. n. carolinae sp. n. coveri sp. n. dexis sp. n. gorgon sp. n. peyrierasi sp. n. rabesoni sp. n. sylvaini sp. n. wardi sp. n. emmae-group 1 species emmae (Emery), 1890 comb. n. = clypeatus Szabo, 1909 = malesiana Forel, 1913 = wheeleri Donisthorpe, 1916 godeffroyi-group 1 species agetos sp. n. grandidieri-group 7 species actis sp. n. ampyx sp. n. bibiolona sp. n. chilo sp. n. dora sp. n. fanano sp. n. grandidieri Forel, 1892 koningsbergeri-group 1 species dicomas sp. n. rogeri-group 14 species admixta sp. n. carisa sp. n. ection sp. n. fronto sp. n. hilaris sp. n. labaris sp. n. luca sp. n. lysis sp. n. milae sp. n. nambao sp. n. norax sp. n. rogeri Emery, 1890 = incisa Godfrey, 1907 = sulfurea Santschi, 1915 sphera sp. n. vazimba sp. n. scotti-group 26 species balux sp. n. bola sp. n. cabira sp. n. chroa sp. n. covina sp. n. deverra sp. n. diota sp. n. diux sp. n. doxa sp. n. epulo sp. n. europs sp. n. finator sp. n. glycon sp. n. inatos sp. n. ipsea sp. n. langrandi sp. n. lexex sp. n. livens sp. n. lucomo sp. n. lura sp. n. odacon sp. n. origo sp. n. ravola sp. n. rubigus sp. n. scotti Forel, 1912 tegar sp. n. KEY TO MALAGASY STRUMIGENYS SPECIES (workers) 1 With head in full-face view a preocular notch present, the ventrolateral margin of the head notched or indented immediately in front of the eye. With head in profile the preocular notch seen to continue vertically as a groove in the side of the head that extends towards the dorsal outline; in the same view preocular notch also seen to extend onto the ventral surface of the head as a transverse preocular groove that runs towards but does not reach the midline. An extremely deep and sharply defined post-buccal groove also present, extending across entire width of head immediately posterior of buccal cavity; post-buccal groove sharply separated from ventral preocular groove 2 – With head in full-face view a preocular notch absent, the ventrolateral margin of the head continuous to the anterior margin of the eye, without trace of a notch or indentation immediately in front of the eye. With head in profile side in front of eye without a vertical groove that extends towards the dorsal outline; in the same view without a transverse preocular groove on the ventral surface of the head. Post-buccal groove vestigial or at most a shallow transverse impression immediately posterior of buccal cavity. 23 2 With head in profile, upper scrobe margins ending, or at least becoming extremely indistinct, at about the level of the eye. 3 – With head in profile, scrobe, and its dorsal margin, extending posteriorly well beyond level of eye 9 3 Preapical teeth absent, at most a small spiniform denticle may be present immediately basal of dorsal apical tooth on right mandible. Apical fork of mandible subtended by a third, shorter spiniform tooth 4 – Preapical teeth present. Apical fork of mandible not subtended by a third spiniform tooth; at most the ventral tooth of the fork may have a minute spur or denticle at its ventral base 7 4 With head in profile, preocular groove meets and is interrupted by the upper scrobe margin before reaching the cephalic dorsum. Scapes relatively shorter: SI 78 - 86 5 – With head in profile, preocular groove extends uninterrupted to the cephalic dorsum, and is not interrupted by the upper scrobe margin. Scapes relatively longer: SI 91 - 132 6 5 Mesonotum with 1 pair of erect hairs on anterior margin. Cephalic dorsum with a transverse row of four erect hairs immediately in front of occipital margin actis – Mesonotum with 2 pairs of erect hairs (can be worn). Cephalic dorsum with a transverse row of six erect hairs immediately in front of occipital margin ampyx 6 Propodeal spines shorter, length of spines about equal to distance between base of spines, distance between base of spines measured distal to basal curvature. Dorsum of head sharply depressed behind vertex, forming a very shallow concave impression before occipital angles; in profile, outline of dorsal margin of occipital corners almost flat. Scapes relatively shorter: SI 91 - 106 chilo – Propodeal spines long, much longer than distance between base of spines. Dorsum of head evenly and gradually curved from vertex to posterior margin of occipital corner; in profile, outline of dorsal margin of occipital corners continuously and gradually curved, not flat. Scapes relatively longer: SI 115 - 132 bibiolona 7 Large species: HL 1.25 - 1.45, HW 0.97 - 1.14. Mandible blade with truncate preapical teeth. Pronotal humerus without a projecting hair. First gastral tergite and sternite without punctate sculpture or at most merely the extreme base of the tergite punctate, the sternite always smooth grandidieri – Smaller species: HL 0.70 - 0.75, HW 0.55 - 0.59. Mandible blade with spiniform preapical teeth. Pronotal humerus with a projecting stiff hair. First gastral tergite and sternite densely punctate over the anterior half or more of the sclerite 8 8 Dorsum of petiole with at least 3 pairs of hairs. Propodeal spines broadly triangular. Declivitous face with standing, posteriorly projecting hair at central lateral margin. Katepisternum smooth and shiny. Colour chocolate brown dora – Dorsum of petiole with one pair of hairs. Propodeal spines narrowly triangular and almost spiniform. Declivitous face without standing hairs. Katepisternum reticulate-punctate. Colour orange brown fanano 9 In full face view, apical portion of the inner margin of the mandible blade concave or scooped out; mandible blade without defined preapical teeth; a rounded tumulus or rarely a minute acute denticle may be present on the posterior apex of the preapical concavity dicomas – In full face view, apical portion of the inner margin not scooped out or concave; mandible with 1 or more sharply defined acute preapical teeth and/or denticles. 10 10 Blade of left mandible with 2 preapical teeth and/or denticles 11 – Blade of left mandible with 1 preapical tooth or denticle 17 11 Pronotal humerus without a freely projecting hair 12 – Pronotal humerus with a flagellate or filiform projecting hair. 14 12 Scapes relatively long, SI > 90 hilaris – Scapes relatively short, SI smaller than 90. 13 13 Mesonotum with a single pair of erect hairs, on anterior margin. In profile, petiole node broadly triangular with a blunt apex.………… luca – Mesonotum with two pairs of erect hairs, a shorter pair posterior to pair on anterior margin. In profile, petiole node evenly convex.…………. milae 14 Pronotal humeri each with a flagellate hair. In profile preocular notch immediately in front of eye narrow, width of notch distinctly less than the maximum diameter of eye. (Cosmopolitan tramp species) rogeri – Pronotal humeri each with a stiff erect filiform hair. In profile preocular notch immediately in front of eye broad, width of notch approximately equal to the maximum diameter of eye. 15 15 Upper scrobe margin posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape. Upper scrobe margin with a narrow projecting lamellate rim above vertical preocular groove on side of head. Mesonotum with a single pair of erect hairs, located on anterior margin lysis – Upper scrobe margin posteriorly with 2 - 4 (usually 3) stiff erect hairs that are longer than hairs on leading edge of scape. Upper scrobe margin without a projecting lamellate rim above vertical preocular groove on side of head; scrobe margin weakly marginate to rounded. Mesonotum with one or two pairs of erect hairs. 16 16 Mesonotum with a single pair of erect hairs, on anterior margin nambao – Mesonotum with two pairs of erect hairs, a shorter pair posterior to pair on anterior margin. norax 17 Head massive, broad (HW 1.28 - 1.65). Propodeal spines recurved anteriorly. vazimba – Head narrower, HW smaller than 0.90. Propodeal spines not recurved anteriorly 18 18 Pronotal humeri each with a long stiff projecting filiform hair 19 – Pronotal humeri without projecting hairs 20 19 Upper scrobe margin posteriorly with 2 - 3 stiff erect hairs that are longer than hairs on leading edge of scape. Head shorter and relatively broader HL 0.80 - 0.88, CI > 80 …… fronto – Upper scrobe margin posteriorly without stiff erect hairs that are longer than hairs on leading edge of scape. Head longer and relatively narrower HL 0.95 - 1.00, CI smaller than 70…… carisa 20 Anterior margin of mesonotum with 2 pairs of stout standing erect hairs, one pair situated slightly anterior and mesad of second pair at anterior lateral margin of mesonotum.. ection – Anterior margin of mesonotum with only a single pair of erect hairs, situated at anterior lateral margin of mesonotum. Rarely, a second pair of hairs is present posterior to the first pair, situated at the midlength of the lateral margin of the mesonotum. 21 21 Upper scrobe margin with a distinct, broad lamellate rim or flange throughout its length. Basal half of scape distinctly and sharply swollen or more or less subcylindrical. Dorsum of head with a transverse row of 6 hairs close to the occipital margin. 22 – Upper scrobe margin without a broad lamellate rim or flange throughout its length, lamellate rim when present limited to region above antennal insertion. Basal half of scape never sharply swollen, scape more or less subcylindrical. Dorsum of head with a transverse row of 4 or 6 erect hairs close to the occipital margin. sphera 22 With head in ventral view, posterior-lateral and lateral margins of post-buccal groove with a lamellate rim; posterior-lateral face of groove concave. admixta – With head in ventral view, posterior and lateral margins of post-buccal groove rounded to bluntly marginate; posterior lateral face of groove never concave, more or less vertical or gently sloping labaris 23 Leading edge of antennal scape a dorsoventrally flattened convex lamella 24 – Leading edge of antennal scape not a dorsoventrally flattened convex lamella; scapes elongate and subcylindrical 47 24 In full-face view the mandibles asymmetric, the left mandible with 3 long or spiniform teeth (including preapical and apical), the right with 4 such teeth. HL 0.55 - 0.70, MI 17 - 33. Eyes usually conspicuous, never with 4 or less ommatidia; if eyes small, then lower scrobe margin marginate, forming a sharp ridge with ventral surface of head. 25 – In full-face view the mandibles symmetric, both blades either with 3 or 4 long or spiniform teeth. HL 0.37 - 0.71, MI 27 - 47. Eyes always small to minute (usually with 4 or less ommatidia); lower scrobe margin rounded, never forming a sharp ridge with ventral surface of head. 33 25 Dorsum of head with scattered punctures, the spaces between them smooth and shiny. Dorsum of promesonotum and petiole node smooth or with smooth surfaces between scattered punctures; without blanketing reticulate-punctate sculpture anywhere on the dorsum. Disc of postpetiole with scattered punctures or glassy smooth, without longitudinal sculpture 26 – Dorsum of head, and usually the dorsal surfaces of promesonotum and petiole node, entirely blanketed with dense fine reticulate-punctate to reticulate-granulate sculpture; without smooth spaces between scattered punctures. Disc of postpetiole usually with fine longitudinal striae or costulae, at least towards the sides. 30 26 Exposed cuticle of petiole node in dorsal view at least as long as broad, usually longer than broad. Pronotal disc as long as broad in dorsal view [length of pronotal disc measured from the anterior margin of the mesothoracic spiracle as seen in dorsal view to point at which the pronotum meets the cervical shield (neck)]. coveri – Exposed cuticle of petiole node in dorsal view conspicuously broader than long. Pronotal disc broader than long in dorsal view 27 27 Dorsal surface of head with appressed spoon-shaped hairs on the lateral portions of the occipital lobes behind the level of the scrobes, these hairs as large as those that border the upper scrobe margins gorgon – Dorsal surface of head without appressed spoon-shaped hairs on the lateral portions of the occipital lobes; such hairs are however present bordering the upper scrobe margins 28 28 Labrum with apical lobes each terminating in a projecting broad fan-like lamella of translucent thin cuticle and a short trigger hair mesad of fan-like lamella; trigger hairs often difficult to see; Base of first gastral sternite with a row of flat, broad, spatulate appressed hairs.. dexis – Labrum with apical lobes each terminating in one or two curved range-finder hairs, without a fan-like lamella of translucent cuticle; Base of first gastral sternite without flat appressed hairs 29 29 Mesonotum without standing hairs. First gastral tergite entirely without standing hairs rabesoni – Mesonotum with a single pair of short straight standing hairs. First gastral tergite with a single pair of straight standing hairs close to the base peyrierasi 30 Erect short hairs entirely absent from dorsal surfaces of alitrunk, waist segments and first gastral tergite; hairs usually absent from cephalic dorsum, at most 1 pair of short simple hairs at occipital angles 31 – Erect short hairs present as follows: a transverse row of 4 across the cephalic dorsum close to the occipital margin, one pair on the mesonotum, one pair posteriorly on the petiole node, two pairs posteriorly on the postpetiolar disc, at least a basal row on first gastral tergite. 32 31 Dorsum of head immediately behind clypeus with a transverse band of scale-like hairs, arranged in several irregular rows; dorsal surface of head without erect hairs. Dorsal surfaces of promesonotum and petiole node entirely blanketed with dense fine reticulate-punctate to reticulate-granulate sculpture. Disc of postpetiole with fine longitudinal striae or costulae, at least towards the sides. Promesonotum flat with bluntly marginate humeral angles. alperti – Dorsum of head immediately behind the clypeus without scale-like hairs. Cephalic dorsum with 1 pair of short simple hairs at occipital angles. Dorsal surfaces of promesonotum and petiole node with only scattered fine reticulate-punctate sculpture. Disc of postpetiole without fine longitudinal striae or costulae. Promesonotum transversely convex dorsally with rounded humeral angles. carolinae 32 Postpetiolar disc finely longitudinally costulate. First gastral tergite without standing hairs between the apical and basal rows wardi – Postpetiolar disc longitudinally reticulate-punctate, often with feeble longitudinal rugulae. First gastral tergite with standing hairs present between the apical and basal rows. sylvaini 33 Antenna with 4 segments. 34 – Antenna with 6 segments. 38 34 Pronotum at humeral angle with a looped, flagellate, or straight clavate hair that projects laterally. 35 – Pronotal humeri without laterally projecting erect hairs 37 35 Pronotal humeri each with a looped or flagellate hair micrans – Pronotal humeri each with a straight clavate hair 36 36 Row of scale-like to broadly spoon-shaped hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Scape strongly back-curved, with a anteriorly projecting subbasal lobe at the bend, and apex of lobe with a projecting broad clavate, almost fan-like hair; preapical tooth of mandible set in the midlength of mandible blade schuetzi – Row of scale-like orbicular hairs on upper scrobe margin terminating at the posterior end with a more or less straight clavate hair. Scape slightly back-curved, leading edge broadening at midlength and convex, not lobe-like, with a row of spoon-shaped hairs; preapical tooth of mandible set in the distal third of the blade’s length (Pantropical tramp species; not yet known from Madagascar, but recorded from neighboring islands.) emmae 37 Pronotal disc without distinct longitudinal costulae; pronotal disc with densely reticulate punctate sculpture as on posterior dorsum of head.. lutron – Pronotal disc with distinct longitudinal costulae and not sculptured as posterior dorsum of head. In between costulae, pronotum smooth or with fine punctulate sculpture levana 38 Pronotal humeri each with a stiff remiform to thickly clavate hair that projects laterally ………………. 39 – Pronotal humeri without laterally projecting erect hairs 40 39 In profile, outline of alitrunk almost flat with a slight medial depression; dorsum of head posterior of frontal lobes and along upper scrobe margin without hairs that are similar in shape to hairs on leading edge of scape; lateral lobe on petiole very small and inconspicuous. Smaller HL smaller than 0.49, HW smaller than 0.40…… alapa – In profile, outline of alitrunk convex in anterior half, more or less flat in posterior half; anterior mesonotal dorsum steeply descending to its posterior half. Dorsum of head posterior of frontal lobes and along upper scrobe margin with hairs that are distinctly narrower than hairs on leading edge of scape; lateral lobe on petiole well developed. Larger HL > 0.55, HW > 0.48 manga 40 Left mandible blade usually with two distinct preapical teeth: a long preapical tooth and a more distal smaller tooth. Larger HL 0.53 - 0.71, HW 0.58 - 0.68 41 – Left mandible with only one distinct, long preapical tooth; a minute denticle may also be present distal of spiniform preapical tooth. Smaller HL 0.40 - 0.49, HW 0.38 - 0.45 42 41 Dorsum of head posterior of frontal lobes and along upper scrobe margin without hairs that are similar in shape to hairs on leading edge of scape; erect short, narrowly clavate hairs present on head, alitrunk, and petiole abdera – Dorsum of head posterior of frontal lobes and along upper scrobe margin with hairs that are similar in shape to hairs on leading edge of scape; erect short, narrowly clavate hairs absent on head, alitrunk, and petiole heliani 42 Apical fork of mandible consisting of 3 spiniform teeth with an intercalary denticle between the apicoventral tooth and center tooth. Dorsum of alitrunk, petiole, postpetiole and gaster blanketed with numerous broadly spoon-shaped to suborbicular hairs. In profile, peduncle of petiole forming a broad translucent cuticular keel ventrally; spongiform tissue limited to a narrow strip at apex of the keel. In profile, ventral spongiform material on postpetiole forming a hollow triangular projection ……… adsita – Apical fork of mandible consisting of 2 spiniform teeth without intercalary teeth between the fork teeth. Dorsum of alitrunk, petiole, postpetiole and gaster without numerous clavate to spoon-shaped hairs. In profile, peduncle of petiole normal, not forming a broad keel ventrally; ventral spongiform tissue on postpetiole not hollow and triangular in outline 43 43 Cephalic dorsum with broad spoon-shaped to orbicular hairs present from posterior clypeal margin to occipital margin; dorsum of petiole with a pair of broadly clavate to remiform hairs bathron – Cephalic dorsum with clavate, spoon-shaped or orbicular hairs absent from posterior third of surface; dorsum of petiole without a pair of broadly clavate to remiform hairs, at most a pair of filiform to narrowly clavate hairs 44 44 Mesonotum with a pair of short erect hairs on anterior margin. Base of first gastral tergite with a continuous row of sharply defined basal costulae mola – Mesonotum without a pair of short erect hairs on anterior margin. Base of first gastral tergite with or without a continuous row of well developed basal costulae 45 45 In profile width of lamella on propodeal declivity distinctly less than half the width of the ventral spongiform strip on the petiole, approximately equal to the width of eye. Base of first gastral tergite with a continuous row of well developed basal costulae. charino – In profile width of lamella on propodeal declivity approximately half the width of the ventral spongiform strip on the petiole. Base of first gastral tergite without a continuous row of sharply defined basal costulae 46 46 Basigastral costulae fine, radiating on each side of a central clear area which is free of costulae; punctulate-reticulate sculpture on tergite restricted to region of basal costulae, remainder of tergite smooth dolabra – Basigastral costulae short, sparse and not sharply defined, gastral tergite covered in punctulate- to granulate-reticulate sculpture, at least on lateral margins. toma 47 Apical fork of right mandible with 2 (occasionally 1) intercalary teeth between the spiniform fork teeth; each blade of mandible with 1 preapical stout tooth. (Mauritius) agetos – Apical fork of mandible without intercalary teeth or denticles between the spiniform fork teeth; each blade of mandible with 2 preapical teeth or preapical teeth absent. 48 48 Apical fork of right mandible composed of 3 spiniform teeth; preapical teeth absent, or at most with a small subapical tooth or denticle on left mandible blade. Propodeal spines long slender and recurved. 49 – Apical fork of right mandible composed of 2 spiniform teeth; each blade of mandible with 2 preapical teeth. Propodeal spines variable in size but not recurved 50 49 Colour chocolate brown. Larger HL 1.24 - 1.35 agra – Colour yellow. Smaller HL 0.99 - 1.17. apios 50 Inner margin of mandible blade with a translucent lamina that extends from proximal preapical tooth, or close to tooth, to level of anterior clypeal margin. Mandible in full-face view with blades almost straight and at full closure parallel. 51 – Inner margin of mandible without a translucent lamina extending from vicinity of proximal preapical tooth to level of anterior clypeal margin. Mandibles in full face view with outer margins shallowly convex; rarely almost straight 57 51 Upper scrobe margin bluntly marginate and gradually fading posterior of eyes, without a sharply defined rim. 52 – Upper scrobe margin distinct and forming a thin sharply defined ridge or lamella posterior of eyes. 55 52 Pronotal humerus with a flagellate hair. Anterior margin of mesonotum with a pair of filiform to narrowly clavate hairs bola – Pronotal humerus without a projecting hair. A single pair of erect clavate hairs present on anterior margin of mesonotum 53 53 In dorsal view, distance of gap between inner margins of mandibular lamellae at full closure approximately equal to or slightly greater than the width of mandible blade. Gland of scape visible as an elongate patch of pale yellow tissue along the apical two thirds of the ventral scape. Postpetiole node more or less shiny and faintly punctulate. Petiole longer, PL 0.35 - 0.41… cabira – In dorsal view, masticatory margin of mandibular lamellae more or less confluent at full closure; distance between inner margins of mandible blades immediately distal of clypeal margin distinctly less than the width of base of mandible blade. Glandular elongate patch of pale yellow tissue not visible near apex of ventral edge of scape. Postpetiole node in dorsal view densely reticulate-punctate. Petiole shorter, PL 0.20 - 0.30… 54 54 Larger, HL 0.75, HW 0.58 SL 0.48 tegar – Smaller, HL 0.57 - 0.62, HW 0.45 - 0.50, SL 0.36 - 0.40 balux 55 Pronotal humerus without a projecting hair. A glandular, elongate patch of pale yellow tissue not visible near apex of ventral edge of scape. Ventral spongiform lamella of petiole often with ventral margin medially notched or distinctly concave. HW 0.64 - 0.77. chroa – Pronotal humerus with a filiform or flagellate hair. Gland of scape visible as a elongate patch of pale yellow tissue near apex of ventral edge of scape. Ventral spongiform lamella of petiole with ventral margin without a medial notch, a shallow medial impression may be present. HW 0.52 - 0.63 56 56 Pronotal humerus with a filiform hair. Hairs on petiole, postpetiole and first gastral tergite filiform. covina – Pronotal humerus with a flagellate hair. Hairs on petiole, postpetiole and first gastral tergite remiform to clavate deverra 57 Pronotum at humeral angle without an erect hair. Mesonotum with a pair of remiform to thickly clavate hairs on anterior margin. diota – Pronotum at humeral angle with a filiform, looped, or flagellate hair. Mesonotum with a pair of flagellate, filiform to narrowly clavate hairs on anterior margin. 58 58 Pronotum with a stiff filiform hair at each humeral angle. Upper scrobe margin posteriorly with 1 or more stiff erect hairs that are longer than hairs on leading edge of scape. 59 – Pronotum with a flagellate or looped hair at each humeral angle. Upper scrobe margin posteriorly almost always without a stiff erect hair that is longer than hairs on leading edge of scape. 60 59 Pronotal dorsum without hairs except for those at the humeral angles. Mesonotum with only one pair of hairs. Colour brownish yellow diux – Pronotal dorsum with standing hairs in addition to those at the humeral angles. Mesonotum with several pairs of hairs. Colour medium to dark brown doxa 60 Dorsum of petiole node mostly shiny and smooth, at most with superficial punctulate sculpture. 61 – Dorsum of petiole node mostly reticulate-punctate or reticulate-punctulate, occasionally the sculpture is weak and the node shiny between punctures, but the disc of petiole is never mostly smooth 63 61 Mesonotum with two pairs of hairs, a flagellate pair on anterior margin with a filiform pair immediately behind. Dorsal lateral margins of head with 2 pairs of standing flagellate hairs near upper scrobe margin. epulo – Mesonotum with one pair of stiff, slightly clavate hairs. Dorsum of head without flagellate hairs…… 62 62 Postpetiole disc with a pair of hairs on posterior margin only. Dorsum of petiole usually without hairs. In full-face view hairs on upper scrobe margin decumbent and sharply bent at basal third. Propodeal lamella well developed, widest section usually distinctly greater in width than the maximum width of eye. Head longer and broader, HL 0.78 - 0.86, HW 0.52 - 0.59. europs – Postpetiole disc with three pairs of hairs. Dorsum of petiole always with a pair of hairs. In full-face view hairs on upper scrobe margin subdecumbent to suberect, curved through entire length. Infradental lamella of propodeum represented by an inconspicuous, very narrow lamellate ridge. Head shorter and narrower, HL 0.57 - 0.64, HW 0.44 - 0.50. finator 63 Mesonotum with only a single pair of erect hairs, located at anterior margin; shorter decumbent hairs may be present posterior to this pair. 64 – Mesonotum with 2 or more pairs of erect hairs; shorter curved hairs may also be present 68 64 Upper scrobe margins fringed with filiform to narrowly spatulate hairs; in full-face view, hairs on upper scrobe margin subdecumbent to suberect, curved through entire length and projecting well beyond the scrobe margin. Mandibles in full face view bowed outwards. In profile ventral spongiform curtain of petiolar peduncle well developed, even at anterior fourth of peduncle. Smaller, HL 0.42 - 0.48, HW 0.34 - 0.38 glycon – Upper scrobe margins fringed with narrowly spatulate to spoon-shaped hairs; in full-face view hairs on upper scrobe margin decumbent and sharply bent at basal third, not projecting well beyond the scrobe margin. Mandibles in full face view almost straight, or with outer margins very shallowly and evenly convex. In profile ventral spongiform curtain of petiolar peduncle variable, either well developed or nearly absent. Larger, HL 0.53 - 0.70, HW 0.40 - 0.53 65 65 Anterior half of first gastral sternite with numerous short suberect hairs. Pronotal dorsum without a longitudinal carina along dorsal midline. Mandible blade with spiniform preapical teeth. rubigus – Anterior half of fist gastral sternite without hairs. Pronotal dorsum often with a longitudinal carina along dorsal midline. Mandible blade with stout preapical teeth. 66 66 Mesopleural hair organ set in a broad concave impression extending along half of the anterior margin of the katepisternum, maximum width of concave impression approximately equal to width of forcoxa. Spongiform appendages of petiole nearly absent. Larger, HL 0.79 - 0.83, HW 054 - 0.57 ipsea – Mesopleural hair organ set in a narrow, concave impression extending much less than one forth of the anterior margin of the katepisternum; maximum width of concave impression less than the maximum width of forfemor. In profile ventral spongiform tissue of petiolar peduncle an irregular, narrow strip across the base of the peduncle or ventral strip well developed. Smaller, HL 0.53 - 0.70, HW 0.40 - 0.53. 67 67 Postpetiole smooth and shiny, even at lateral margins. In profile ventral spongiform curtain of petiolar peduncle well developed across entire length of peduncle, width of curtain at anterior third of peduncle is approximately equal to or greater than maximum width of eye. scotti – Postpetiolar disc longitudinally striolate and usually feebly punctate on lateral margins. In profile ventral spongiform tissue of petiolar peduncle reduced or nearly absent across anterior third of peduncle, usually the deepest point in this section is distinctly less than maximum width of eye.. inatos 68 In profile ventral spongiform tissue of petiolar peduncle a narrow, irregular strip that is often not continuos across the base of the peduncle, the majority of the strip in the anterior third of the peduncle is distinctly less than the maximum width of eye (excluding spongiform tooth if present) 69 – In profile ventral spongiform curtain of petiolar peduncle conspicuous and well developed across the base of the peduncle, entire width of curtain approaches maximum width of eye. 72 69 Lateral margins of first gastral tergite with appressed fine hairs. Postpetiole with numerous hairs of variable length… lexex – Lateral margins of first tergite without appressed hairs. Postpetiole with three pairs of erects hairs of similar length 70 70 Dorsum of pronotum without erect hairs except for a flagellate hair at each humeral angle. livens – Dorsum of pronotum with 1 or more pairs of short or long suberect or erect hairs in addition to the flagellate hair at each humeral angle 71 71 In profile anterior end of ventral spongiform lamella of petiolar peduncle produced into a ventrally directed triangular tooth lucomo – In profile anterior end of ventral spongiform lamella of petiolar peduncle at most a small rounded lobe, not produced into a tooth. lura 72 Dorsum of head immediately behind clypeus densely clothed with curved, decumbent spoon-shaped ground pilosity. Pronotal dorsum densely reticulate-punctate as on head and with faint longitudinal striolate sculpture. Anterior half of first gastral sternite with erect filiform hairs ravola – Cephalic dorsum densely clothed with erect to curved filiform to narrowly spatulate hairs ground-pilosity. Pronotal dorsum longitudinally striolate on a smooth surface or with superficial punctulate sculpture. Anterior half of first gastral sternite with or without erect filiform hairs. 73 73 Mesonotum with three pairs of erect hairs. Pronotum with at least one pair of stout erect hairs between the flagellate hairs at the pronotal humeri origo – Mesonotum with two pairs of erect hairs. Pronotum without stout erect hairs between the flagellate hairs at the pronotal humeri. 74 74 Anterior half of first gastral sternite with erect filiform hairs. Upper scrobe margins fringed with filiform to narrowly spatulate hairs; in full-face view, hairs on upper scrobe margin subdecumbent to suberect, curved at apex, and projecting well beyond the scrobe margin. Smaller, HL 0.48 - 0.51, HW 0.37 - 0.41. odacon – Anterior half of first gastral sternite without erect hairs. Upper scrobe margins fringed with spatulate hairs; in full-face view hairs on upper scrobe margin decumbent and sharply bent at basal third, not projecting well beyond the scrobe margin. Larger, HL 0.56 - 0.59, HW 0.44 - 0.47 langrandi adsita-group DIAGNOSIS OF WORKER Apical fork of mandible with 3 spiniform teeth: apicodorsal tooth is subtended by a smaller apicomedian tooth, which itself is subtended by a denticle and the apicoventral tooth, which is similar in size to the apicomedian tooth; intercalary denticle cannot be seen when the mandibles are closed. Mandible with 1 spiniform preapical tooth, located at about the distal third of the length. Mandible in full face view short (MI 29 - 35), narrowly linear and outcurved; dorsum, proximal of the preapical tooth, slightly concave Funicular segments 2 and 3 of antenna small and often difficult to discern Leading edge of scape a dorsoventrally flattened convex lamella. Upper scrobe margins in full-face view widely divergent behind the frontal lobes. Spongiform appendages of petiole a narrow strip; lateral lobes absent. Postpetiole with lateral and ventral lobes. Infradental lamella of propodeum well developed into a wide strip below the triangular propodeal spines. Pilosity. Spatulate to spoon-shaped hairs present on dorsum of head behind clypeus, anterior clypeal margin, lateral clypeal margins, upper scrobe margins (curved anteriorly) and leading edges of scapes (curved toward scape apex). Dorsal surfaces of mandibles with elongate filiform hairs that are directed towards the midline. Dorsal surface of postpetiole, and gaster with spatulate to spoon-shaped hairs; entire body lacking flagellate hairs. Sculpture. Fine dense reticulate-punctate sculpture blankets the entire dorsum of the head, alitrunk and petiole; postpetiole and gaster more or less unsculptured except for basigastral costulae. Glands. Gland of scape near the apex on the ventral surface not apparent. Apicofemoral gland bola not visible. Apicotibial gland bola visible but not distinct on hind and midtibia. Gland at base of fortibial spur not visible. Apicotarsal glands not visible. Mesopleural hair-filled gland visible and set in a narrow circular notch. S. adsita is most similar to species in the arnoldi- and emmae-groups. S. adsita differs from the emmae-group in having 6 antennal segments. S. adsita differs from the arnoldi-group in having the apical fork consist of 3 spiniform teeth with an intercalary denticle between the apicoventral tooth and center tooth. The antenna with six segments, structure of antennal scape, and the mandibular dentition distinguished the adsita-group from other Strumigenys in Madagascar. Strumigenys adsita Fisher sp. n. (Figs 381, 409) HOLOTYPE WORKER. TL 2.1 , HL 0.48, HW 0.44, CI 91, ML 0.14, MI 29, SL 0.25, SI 58, PW 0.28, AL 0.51. Characters of adsita-group. Blade of mandible with 1 spiniform tooth located at about the distal third of the blades length. Apicodorsal spiniform tooth is subtended by a smaller spiniform tooth which itself is subtended by one denticle and a spiniform apicoventral tooth which is similar in size as middle apical spiniform tooth. Intercalary denticle cannot be seen when the mandibles are closed. Cephalic dorsum including clypeus, upper scrobe margin, dorsum of alitrunk, including lateral margin of declivity, petiole, postpetiole, and gaster blanketed with spatulate to spoon-shaped hairs that are similar to the hairs on leading edge of scape. Dorsum of head, alitrunk dorsum and sides, and petiole reticulate-punctate. In profile, promesonotal dorsum very shallowly convex; propodeal dorsum sloping posteriorly to the declivity. Posterior promesonotum meeting sides in a blunt margin. In profile, spongiform lamella continuous along propodeal declivity. In profile, peduncle of petiole with a broad translucent keel ventrally; spongiform tissue limited to a narrow strip at apex of the keel. In profile, ventral spongiform material on postpetiole forming a hollow triangular projection. Base of first gastral tergite with basal costulae radiating medially on each side of a central clear area. Color pale brown. PARATYPE WORKERS. TL 1.9 - 2.1, HL 0.46 - 0.49, HW 0.41 - 0.44, CI 86 - 94, ML 0.14 - 0.16, MI 29 - 35, SL 0.24 - 0.27, SI 56 - 64, PW 0.27 - 0.28, AL 0.49 - 0.56 (11 measured). As holotype. Holotype worker, Madagascar: grassland near Forêt Ankazomivady, 28 km SSW Ambositra, 1670 m, 20 deg. 46 min. 30 seg. S, 47 deg. 10 min. 6 seg. E, 12 Jan 1998, grassland, nest in soil in 2 adjoining cells, 9.5 cm from surface, found by digging, SAM#011222 (H.G. Robertson) (SAM). Paratypes. 20 workers and 5 queens (4 alate and 1 dealate) with same data as holotype (BMNH, MCZ). The enormously expanded keel of the peduncle makes adsita one of the most easily recognized Malagasy Strumigenys. In addition, the apical fork of mandible is composed of 3 spiniform teeth with an intercalary denticle between the ventral tooth and middle tooth. These character coupled with the presence of spoon-shaped hairs on all dorsal surfaces and the triangular and hollow ventral spongiform tissue of the post-petiole should make confusion of adsita with any other species impossible. apios-group DIAGNOSIS OF WORKER Mandible in full-face view with blades almost straight and at full closure parallel. Dentition of mandibles. Apical fork of mandible with three spiniform teeth, without intercalary teeth or denticles, ventral apical tooth shortest. Preapical teeth absent. MI 54 - 68. Scape slender and subcylindrical, SI 119 - 138. Labral range-finder/trigger-hair paired, combined, and directed apically. Preocular notch is vestigial or absent. Ventral preocular impression in the head absent. Eye with maximum diameter exceeding, the maximum width of the scape. Glands. Gland of scape visible as an elongate patch of pale tissue along the midsection of the ventral scape. Apicofemoral gland decreasing in size from hind femur where it is easily visible to the profemur where it is minute to absent. Apicotibial gland bola absent on all tibia of workers (apios) or present on hind and fortibia (agra). Gland at base of fortibial spur conspicuous. Apicotarsal glands visible on at least first three tarsi, decreasing in size from basal tarsi where it is elongate to the third tarsal segment where it is oval. Mesopleural hair-filled gland visible and set in a narrow circular notch or a broad concave impression. Spongiform appendages of petiole absent. Postpetiole with a reduced or absent ventral and lateral lobes; spongiform collar present. Pilosity. Pronotal humerus usually without, a projecting specialized hair. Dorsolateral margin of head never possessing a freely projecting hair near level of apex of scrobe; upper scrobe margin without row of hairs. Cephalic ground-pilosity scale-like. Cephalic dorsum with 4 standing hairs, arranged as a transverse row near occipital margin; vertex without standing pair of hairs. Dorsum of thorax without standing hairs. First gastral tergite with standing hairs which are simple or slightly thickened apically. Sculpture. Head, alitrunk dorsum and petiole reticulate-punctate. Gaster unsculptured except for basigastral costulae. S. agra and apios are easily distinguished from all other Malagasy species of Strumigenys by the combination of long cylindrical scapes, apical fork of mandible composed of 3 spiniform teeth, preapical teeth usually absent, propodeal spines long, slender and recurved and the absence of a preocular notch. The 2 species included here are convergent on the southeast Asian szalayi-group and the kraepelini-complex of the mayri-group but are clearly derived from Malagasy grandidieri-group. Strumigenys agra Fisher sp. n. (Figs 389, 410) HOLOTYPE WORKER. TL 4.9, HL 1.13, HW 0.76, CI 67, ML 0.69, MI 60, SL 0.92, SI 122, PW 0.45, AL 1.44. Characters of apios-group. Upper scrobe margins evenly and shallowly convex, rounding cleanly into the sides of the occipital lobes without trace of an angle, the two together forming a single evenly curved surface in full-face view. Eyes large, the maximum diameter of the eye distinctly greater than the maximum width of the scape. Antennal scapes long (SI 122) with their leading edges equipped with a row of slender hairs which curve towards the apex and which are slightly flattened or spoon-shaped apically. Ventral gland of scape visible as an elongate patch of pale tissue along the midsection of the ventral scape. Cephalic dorsum densely clothed with scale-like ground-pilosity; the upper scrobe margins without a row of hairs. Cephalic dorsum with 4 simple standing hairs arranged in a transverse row close to the occipital margin. Mesopleural hair-filled gland set in circular notch. Dorsum of alitrunk without standing hairs. Ground-pilosity on alitrunk as on head. Posterior portion of mesonotum shallowly depressed below level of pronotum; propodeal dorsum concave. Propodeal teeth long, slender and curved anterolaterally; infradental lamella absent. Alitrunk dorsum and sides reticulate-punctate. Petiole node in dorsal view reticulate-punctate and much longer than broad. Postpetiole reticulate-punctate. Spongiform appendages of pedicel absent. Postpetiole without distinct lateral and ventral spongiform lobes. Basigastral costulae fine and superficial; gaster smooth and shiny where clean. Dorsal surfaces of postpetiole with a pair posteriorly projecting simple hairs, and posterior margin of gastral segments with standing hairs which are simple or very slightly thickened apically. Colour chocolate brown. PARATYPE WORKERS. TL 4.8 - 5.4, HL 1.24 - 1.35, HW 0.68 - 0.77, CI 53 - 58, ML 0.69 - 0.86, MI 54 - 68, SL 0.85 - 0.95, SI 123 - 133, PW 0.41 - 0.47, AL 1.33 - 1.51. As holotype. Holotype worker, Madagascar: 6.9 km NE Ambanizana, 15 deg. 34 min. S, 50 deg. 00 min. E, 825 m, 2.ix.1993, sifted litter (leaf mold, rotten wood), rainforest, #976 (20)-10 (B. L. Fisher). (MCZ). Paratypes. 4 workers 1 queen (dealate) with same data as holotype but coded (28)-12, (45)-12, (46)-13, (49)-9, (29)-12. (BMNH, SAM). S. agra and apios are closely related and are immediately recognizable with their 3 spiniform apical fork, recurved spines, absence of spongiform tissue on a cylindrical-shaped petiole. S. agra is distinguished by its larger size, and chocolate brown colour. Strumigenys apios Fishersp. n. HOLOTYPE WORKER. TL 4.0, HL 1.02, HW 0.60, CI 59, ML 0.59, MI 58, SL 0.80, SI 133, PW 0.36, AL 1.08. Characters of apios-group Mandibular blades almost straight and at full closure parallel. Apical fork of right mandible of 3 stout spiniform teeth, ventral apical tooth shortest; preapical teeth absent. Apical fork of left mandible with 2 stout spiniform teeth, small tooth present at base of ventral fork tooth; small subapical tooth present proximal of dorsal fork. Upper scrobe margins evenly and shallowly convex, rounding cleanly into the sides of the occipital lobes without trace of an angle, the two together forming a single evenly curved surface in full-face view. Eyes large, the maximum diameter of the eye distinctly greater than the maximum width of the scape. Antennal scapes long (SI 133) with their leading edges equipped with a row of slender hairs which curve towards the apex and which are slightly flattened or spoon-shaped apically. Cephalic dorsum with appressed clavate to spoon-shaped ground-pilosity; the upper scrobe margins without a row of hairs. Cephalic dorsum with 4 simple standing hairs arranged in a transverse row close to the occipital margin. Mesopleural hair-filled gland set in a concave impression. Dorsum of alitrunk without standing hairs. Ground-pilosity on alitrunk sparse. Posterior portion of mesonotum shallowly depressed below level of pronotum; propodeal dorsum gently sloping to declivity. Propodeal teeth long, slender and curved anterolaterally; infradental lamella absent. Alitrunk dorsum reticulate-punctate. Petiole node reticulate-punctate and much longer than broad. Postpetiole reticulate-punctate. Spongiform appendages of pedicel absent. Lateral and ventral spongiform lobes of postpetiole vestigial. Basigastral costulae fine and superficial; gaster smooth and shiny where clean. Dorsal surfaces of postpetiole with a pair posteriorly projecting simple hairs, and posterior margin of gastral segments with standing hairs which are simple or very slightly thickened apically. Colour yellowish brown PARATYPE WORKERS. TL 4. - .5, HL 1.01 - 1.13, HW 0.64 - 0.70 CI 62 - 64, ML 0.59 - 0.63, MI 56 - 62, SL 0.78 - 0.84, SI 119 - 129, PW 0.36 - 0.41, AL 1.07 - 1.19. As Holotype. Holotype worker, Madagascar: 11.0 km WSW Befingotra, Res. Anjanaharibe-Sud, 14 deg. 45 min. S, 49 deg. 27 min. E, 1565 m, 16.xi.1994, sifted litter (leaf mold, rotten wood), montane rainforest #1232 (28)-4. (B. L. Fisher) (MCZ). Paratypes. 3 workers with same data as holotype, 2 workers with same data as holotype but coded (49)-3. (BMNH, SAM). Non-paratypic material examined. Madagascar: R.S. Manongarivo, 17.3 km 218 deg. SW Antanambao, 1580 m (B. L. Fisher); R.S. Manongarivo, 20.4 km 219 deg. SW Antanambao, 1860 m (B. L. Fisher); 6 km ESE Andasibe (=Périnet), 900 m (P.S. Ward). Measurements of this material extends the range shown by the type-series: HL 0.99 - 1.17, HW 0.59 - 0.65, CI 55 - 62, ML 0.58 - 0.73, MI 59 - 62, SL 0.79 - 0.89, SI 128 - 138 (3 measured). The single specimen from Andasibe is slightly larger and narrower, has symmetric mandibles, apical fork of both blades with 3 stout spiniform teeth and no subapical teeth or denticles and sides of alitrunk with more extensive reticulate-punctate sculpture. Additional collections will be necessary to determine if this specimen represent a sibling species S. apios is distinguished from its close relative agra by its smaller size, and yellowish brown colour. arnoldi-group DIAGNOSIS OF WORKER Mandible in full-face view short (MI 27 - 47); blade of mandible narrow, linear and outcurved in full-face view; the dorsum, proximal of the basalmost tooth, slightly concave. Dentition of mandibles symmetric; either with 3 or 4 teeth and denticles in total. In all species both mandible have 3 long teeth, one long preapical tooth and two apical spiniform teeth. In some species, a smaller tooth or denticle may be present between the long preapical tooth and the dorsal most tooth of the apical fork. When the 4th tooth is present, it is often weakest on the left mandible. Antennae usually 6-merous with funicular segments 2 and 3 small and often difficult to discern, or antennae 4-merous (micrans, schuetzi, lutron, levana). Leading edge of scape a dorsoventrally flattened convex lamella. Eyes very small or vestigial, usually with 4 or less ommatidia. Upper scrobe margins in full-face view widely divergent behind the frontal lobes. Ventrolateral margin of head without trace of a preocular notch, the margin continuos in from of the eye. Ventral surface of ahead without a preocular transverse groove but postbuccal groove is distinct. Promesonotum flat to slightly convex dorsally and bluntly marginate laterally. Glands. Scape gland absent (bathron, charino, dolabra, lutron, manga, micrans, mola, schuetzi, toma) or visible as a elongate patch near apex of ventral scape (abdera, alapa, heliani, levana). Apicofemoral and apicotibial gland bola absent on all femora and tibia of workers. Gland at base of fortibial spur conspicuous. Apicotarsal glands absent (alapa, bathron, toma) or visible on at least first three tarsi of fortarsi, decreasing in size from basal tarsi where it is elongate to the third tarsal segment where it is oval. Mesopleural hair-filled gland visible and set in a circular notch. Spongiform appendages of petiole usually well developed into a ventral curtain (narrow strip in abdera); lateral lobes present. Postpetiole with lateral and ventral lobes. Infradental lamella of propodeum usually well developed into a wide strip below the triangular propodeal spines (narrow in charino, micrans, mola). Pilosity. Head with curved spatulate to spoon-shaped or orbicular shaped hairs present on dorsum of head behind clypeus at least on anterior half (absent in abdera), anterior clypeal margin, lateral clypeal margins, upper scrobe margins (curved anteriorly) (short, simple appressed hairs in abdera), and leading edges of scapes (curved toward scape apex). Dorsal surfaces of mandibles with elongate filiform hairs that are directed towards the midline. Dorsum of head without erect hairs or with a transverse row of 4 hairs close to the occipital margin (abdera, alapa, charino, levana, lutron, manga, micrans, mola). Pronotum without a laterally projecting hair, or with a flagellate hair (micrans) or with a straight clavate hair (alapa, manga, schuetzi). Mesonotum without erect hairs, or with one pair on the mesonotum (abdera, alapa, lutron, manga, micrans, mola) or with two pairs (levana). Dorsal surface of postpetiole, and gaster with short filiform to narrowly clavate hairs; entire body usually lacking flagellate hairs (pronotal humeri with a flagellate hair in micrans). Sculpture. Fine dense reticulate-punctate to reticulate-granulate sculpture blankets the entire dorsum of the head; the pronotum reticulate-punctate and occasionally with longitudinal costulae; remainder of the dorsal alitrunk reticulate-punctate (propodeum not reticulate-punctate in manga); petiole with dense reticulate-punctate sculpture or with faint reticulate-punctate sculpture that is almost effaced. Gaster unsculptured except for basigastral costulae. Members of this group are most similar to species in the emmae-, adsita- and dexis-groups but differ in mandibular dentition and hairs on upper scrobe margin. The upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair (as in emmae-group), apical fork of mandible is never composed of 3 spiniform teeth with an intercalary denticle between the ventral tooth and middle tooth (adsita-group) and mandibles are symmetric with both blades either with 3 or 4 teeth (asymmetric in dexis-group). In addition, the arnoldi-, emmae-, and adsita-group can be distinguished from the dexis group by the following characters: eyes always small to minute (usually with 4 or less ommatidia) and the lower scrobe margin rounded, never forming a sharp ridge with ventral surface of head. In the dexis-group, eyes are usually conspicuous, never with 4 or less ommatidia, but if eyes small, then the lower scrobe margin marginate, forming a sharp ridge with ventral surface of head. The arnoldi-group is also very speciose in the Afrotropical region (see there). The group diagnosis above is somewhat modified from the Afrotropical, to give a best representation of the Malagasy fauna. Within this region, members of this group fall into 4 discrete complexes of related species. 1) abdera-complex (abdera, bathron, charino, heliani, manga, mola). Each mandible with one spiniform preapical tooth. A smaller tooth or denticle is present between the long preapical tooth and the dorsal most tooth of the apical fork. The tooth is weakest on the left mandible and may be represented by a minute denticle. Antenna with 6 segments. 2) alapa-complex (alapa, dolabra, toma). Right and left mandible blades with one spiniform preapical tooth each, without preapical denticles. Antenna with 6 segments. 3) lutron-complex (levana, lutron, micrans). Each mandible with one spiniform preapical tooth. A smaller tooth or denticle is present between the long preapical tooth and the dorsal most tooth of the apical fork. The tooth is weakest on the left mandible. Antenna with 4 segments. 4) schuetzi-complex (schuetzi). Right and left mandible blades with one spiniform preapical tooth each, without preapical denticles. Antenna with 4 segments. Strumigenys abdera Fisher sp. n. (Figs 382) HOLOTYPE WORKER. TL 2.9, HL 0.70, HW 0.65, CI 93, ML 0.31, MI 44, SL 0.37, SI 57, PW 0.38, AL 0.77. Characters of abdera-complex. Blade of mandible with 4 teeth: 2 preapical teeth and an apical fork of 2 spiniform teeth. Distal preapical tooth smaller than basal most preapical tooth and spiniform teeth. A small denticle is present at base of ventral apical tooth. Hairs on the dorsum of head posterior of frontal lobes and along upper scrobe margin are not similar in shape to hairs on leading edge of scape. Hairs along upper scrobe margin short, simple and appressed. In profile, promesonotal dorsum convex; propodeal dorsum convex anteriorly, sloping posteriorly to the declivity. Ground pilosity of dorsum of head posterior to frontal lobes and promesonotum consisting of numerous small scale-like to orbicular hairs, most of which are closely applied to the surface. Erect, short and narrowly clavate hairs present on head and alitrunk as follows: a transverse row of 4 across the cephalic dorsum close to the occipital margin, one pair on the mesonotum. Hairs on petiole, postpetiole, and gaster filiform to clavate. Postpetiolar disc with fine dense reticulate-punctate to reticulate-granulate sculpture. In profile, ventral spongiform lamella of petiole not well developed, tapering to a narrow strip near pedicle base. Propodeal teeth a blunt triangle and incorporated in the infradental lamellae. Infradental lamellae a narrow strip. Color pale brown. PARATYPE WORKER. TL 2.8 - 3.0, HL 0.70 - 0.71, HW 0.65 - 0.68, CI 93 - 96, ML 0.29 - 0.31, MI 42 - 44, SL 0.36 - 0.38, SI 54 - 56, PW 0.37 - 0.40, AL 0.69 - 0.72 (4 measured). As holotype. Holotype worker, Madagascar: 40 km S Ambalavao, Res. Andringitra 22 deg. 13 min. S, 46 deg. 58 min. E, 1275 m, 15.x.1993. sifted litter (leaf mold, rotten wood), montane rainforest, #793 (47)-6 (B. L. Fisher) (MCZ). Paratypes. 4 worker same data as holotype but coded (49)-6, (23)-8 (BMNH, SAM). Non-paratypic material examined. Madagascar: 29 km SSW Ambositra, Ankazomivady 1700 m (B.L. Fisher). Measurements of this material extends the range shown by the type-series: HL 0.63 - 0.67, HW 0.58 - 0.64, CI 90 - 96, ML 0.27 - 0.30, MI 43 - 46, SL 0.34 - 0.39, SI 57 - 61 (4 measured). S. abdera is easily distinguished from other species in the arnoldi-group by the presence of 2 preapical teeth and the absence of curved spatulate to spoon-shaped hairs on the dorsal surfaces of the head, alitrunk and petiole. Strumigenys alapa Fisher sp. n. (Fig. 383) HOLOTYPE WORKER. TL 1.7, HL 0.44, HW 0.38, CI 85, ML 0.14, MI 31, SL 0.23, SI 62, PW 0.23, AL 0.44. Characters of alapa-complex. Blade of mandible with 3 teeth: 1 preapical tooth and an apical fork of 2 spiniform teeth. Dorsum of head posterior of frontal lobes and along upper scrobe margin with spoon-shaped hairs that are similar in shape to hairs on leading edge of scape. In dorsal view, occipital angles without spoon-shaped hairs. Cephalic dorsum with a transverse row of 4 erect, short clavate hairs near occipital margin. Pronotal humeral angle with an erect stiff clavate hair. Mesonotum with a pair of short erect hairs, located at anterior margin. In profile, promesonotal dorsum very shallowly convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Spongiform tissue well developed on declivity of propodeum, petiole and postpetiole. Propodeal teeth incorporated in the infradental lamellae. Infradental lamella broad, more than half as broad as ventral lamella of petiole. Color dull yellow to pale brown. PARATYPE WORKERS. TL 1.7 - 1.9, HL 0.43 - 0.48, HW 0.36 - 0.39, CI 81 - 84, ML 0.13 - 0.15, MI 29 - 32, SL 0.23 - 0.26, SI 60 - 69, PW 0.21 - 0.24, AL 0.45 - 0.48 (4 measured). As holotype. Holotype worker, Madagascar: Prov. Toliara, Beza-Mahafaly, 27 km E Betioky, 23 deg. 38 min. S, 44 deg. 38 min. E, 135 m, 23.iv.1997, sifted litter (leaf mold, rotten wood), tropical dry forest #1476 (L.O.)-1 (B.L. Fisher) (MZC). Paratypes. 1 workers and 1 queen (dealate) with same data as holotype; 3 workers and 1 queen (dealate) with same data has holotype but coded (14)-1, (42)-1, (12)-1. (BMNH, SAM). S. alapa is distinguished from other species in the arnoldi-group by having: 1) Head and upper scrobe margin with broadly spatulate to spoon-shaped hairs. 2) Pronotal humeri each with a single stiff remiform to thickly clavate hair that projects laterally. 3) In profile, alitrunk almost flat; mesonotum in profile without a deep depression posteriorly before meeting the propodeum. Strumigenys bathron Fisher sp. n. HOLOTYPE WORKER. TL 2.0, HL 0.47, HW 0.45, CI 96, ML 0.17, MI 36, SL 0.26, SI 58, PW 0.26, AL 0.48. Characters of abdera-complex. Blade of mandible with 3 teeth: 1 long preapical tooth and an apical fork of 2 spiniform teeth. Dorsum of head from posterior clypeal margin to occipital margin including occipital angles and along upper scrobe margin with spoon-shaped hairs that are similar in shape to hairs on leading edge of scape. Pronotal humeral angle and anterior margin of mesonotum without erect stiff hairs. Dorsum of petiole with a pair of broadly clavate to remiform hairs on posterior lateral margin. In profile, promesonotal dorsum convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Cuticle on anterior half of propodeal declivity alveolate. Spongiform tissue well developed on declivity of propodeum, petiole and postpetiole. Propodeal teeth incorporated in the infradental lamellae, with only a small point projecting. Infradental lamellae broad, more than half as broad as ventral lamellae of petiole. Disc of postpetiole smooth; in dorsal view completely surrounded in spongiform tissue, forming a narrow band along anterior lateral angles. Color dull yellow to pale brown. PARATYPE WORKERS. TL 1.8 - 1.9, HL 0.45, HW 0.43, CI 95 - 96, ML 0.15, MI 33 - 34, SL 0.22 - 0.24, SI 51 - 55, PW 0.23 - 0.25, AL 0.46 - 0.47 (2 measured). As holotype. Holotype worker, Madagascar: 6.5 km SSW Befingotra, Res. Anjanaharibe-Sud, 14 deg. 45 min. S, 49 deg. 30 min. E., 875 m, 19.x.1994. Sifted litter (leaf mold, rotten wood), rainforest #1070 (L.0.)-15 (B.L. Fisher) (MCZ). Paratypes. 2 workers with same data as holotype but coded (8)-9, (50)-1 (BMNH). Non-paratypic material examined. Madagascar: 5 km SW Antalaha 50 m (G. D. Alpert); 6.9 km NE Ambanizana, Ambohitsitondroina 825 m (B.L. Fisher); 5.3 km SSE Ambanizana, Andranobe, 425 m (B.L. Fisher). Measurements of this material extends the range shown by the types series: HL 0.41 - 0.46, HW 0.41 - 0.43, CI 94 - 97, ML 0.13 - 0.16, MI 32 - 35, SL 0.22 - 0.23, SI 53 - 57 (4 measured). The sample from 6.9 km NE Ambanizana differs slightly in the diagnostic characters of the type material. In this single specimen, the clavate hairs on petiolar dorsum are broader and the ventral spongiform lamella on the petiole is narrower. Additional collection may reveal that this is actually a sibling species. S. bathron is distinguished from other species in the arnoldi-group with 6 antennal segments by having the cephalic dorsum with broad spoon-shaped to orbicular hairs present on posterior third, dorsum of petiole with a pair of broadly clavate to remiform hairs; and the pronotal humeri without erect hairs. Strumigenys charino Fisher sp. n. HOLOTYPE WORKER. TL 1.8, HL 0.44, HW 0.39, CI 89, ML 0.17, MI 38, SL 0.21, SI 54 PW 0.26, AL 0.47. Characters of abdera-complex. Blade of mandible with 3 teeth: 1 preapical tooth and an apical fork of 2 spiniform teeth; minute denticle present on left mandible between preapical tooth and dorsal tooth of apical fork. Cephalic dorsum posterior of clypeal margin with rows of spoon-shaped hairs on anterior two thirds; upper scrobe margin with spoon-shaped hairs. Cephalic dorsum with a transverse row of 4 erect, short clavate hairs near occipital margin. Pronotal humerus without a projecting hair; mesonotum without standing hairs. Dorsum of alitrunk with short spatulate ground-pilosity. In profile, promesonotal dorsum very shallowly convex; propodeal dorsum more or less flat anteriorly, sloping posteriorly to the declivity and rounding into the sides. Propodeal tooth a small denticle incorporated in the very narrow infradental lamellae; in profile, width of lamella approximately the width of eye. Ventral spongiform tissue well developed and conspicuous on petiole and postpetiole. Base of first gastral tergite with a continuous row of well developed basal costulae. Color dull yellow to pale brown. PARATYPE WORKERS. TL 1.8, HL 0.42 - 0.44, HW 0.38 - 0.40, CI 91 - 93, ML 0.16 - 0.17, MI 39 - 41, SL 0.20 - 0.22, SI 50 - 57, PW 0.24 - 0.26, AL 0.45 - 0.46 (3 measured). As holotype. Holotype worker, Madagascar: Fotodriana, Cap Masoala, 25 m 15 deg. 41 min. 49 sec. S, 50 deg. 16 min. 13 sec. E, 27.xi.1993. rainforest, Winkler app. 160.13981w (G. D. Alpert) (MCZ). Paratypes. 1 worker with same data as holotype but coded 160.13982w; 2 workers (one with gaster missing) with same data has holotype but coded 160.3635w, 160.3636w and labeled lowland rainforest (Alpert et al.) (BMNH, SAM). Non-paratypic material examined. Madagascar: F.C. Andriantantely 530 m (H. J. Ratsirarson). Measurements of this material extends the range shown by the type-series: HL 0.45 - 0.48, HW 0.43 - 0.45, CI 95 - 96, ML 0.17 - 0.19, MI 38 - 40, SL 0.23 - 0.25, SI 53 - 56 (3 measured). Within the arnoldi-group with 6 antennal segments, charino is separated from all other members by having: 1) Cephalic dorsum posterior of clypeal margin with rows of spoon-shaped hairs on anterior two thirds. 2) Pronotal humeri and mesonotum without erect hairs. 3) Base of first gastral tergite with a continuous row of well developed basal costulae. 4) In profile, propodeal infradental lamella very narrow, approximately the width of eye. Strumigenys dolabra Fisher sp. n. HOLOTYPE WORKER. TL 1.7, HL 0.40, HW 0.38, CI 94, ML 0.11, MI 28, SL 0.19, SI 50, PW 0.23, AL 0.45. Characters of alapa-complex. Blade of mandible with 3 teeth: 1 preapical tooth and an apical fork of 2 spiniform teeth. Anterolateral margin of clypeus with a spoon-shaped hair curved medially that is larger and more conspicuous than hairs found on anterior margin of clypeus. Cephalic dorsum posterior of clypeal margin with spoon-shaped hairs on anterior two thirds; upper scrobe margin with spoon-shaped hairs. Pronotal humerus without a projecting a hair; mesonotum without standing hairs. In profile, promesonotal dorsum very shallowly convex anteriorly; propodeal dorsum gradually sloping posteriorly to the declivity and posteriorly meeting the sides in a blunt diverging angle. Propodeal dorsum meeting the declivity in a blunt angle without a noticeable tooth. Ventral spongiform tissue well developed and conspicuous on propodeum, petiole and postpetiole. In profile, spongiform lamella on propodeal declivity broad, approximately half the width of ventral spongiform curtain on petiole. Base of first gastral tergite with few basal costulae. Punctulate-reticulate sculpture on tergite restricted to region of basal costulae, remainder of tergite smooth. Hairs on postpetiole and gaster filiform. Color pale brown. Holotype worker, Madagascar: Prov. Toliara, southern Isoky-Vohimena Forest, 22 deg. 41 min. S, 44 deg. 50 min. E, 730 m, 21.i.1996, sifted litter (leaf mold, rotten wood), tropical dry forest, #1312 (5)-3 (S. Razafimandimby) (MCZ). Within the arnoldi-group with 6 antennal segments, dolabra and toma are separated from all other members by having: – Cephalic dorsum without hairs on posterior third which are similar in shape to hairs on leading edge of scape. – Pronotal humeri and mesonotum without erect hairs. – Base of first gastral tergite with few basal costulae. – In profile, propodeum terminating in a blunt angle. – Infradental lamella on propodeum broad. S. dolabra is distinguished from toma as follows: dolabra 1) First gastral tergite with punctulate-reticulate sculpture on tergite restricted to region of basal costulae, remainder of tergite smooth. 2) In dorsal view, cephalic dorsum with clavate to spoon-shaped hairs on anterior two-thirds, rows of hairs absent from vertex, posterior of posterior end of upper scrobe margin. toma 1) First gastral tergite covered in punctulate- to granulate-reticulate sculpture, at least on lateral margins posteriorly. 2) In dorsal view, cephalic dorsum with broadly scale-like to orbicular shaped hairs on anterior two thirds, extending on to vertex, posterior of posterior end of upper scrobe margin. Strumigenys heliani Fisher sp. n. (Figs 384, 411) HOLOTYPE WORKER. TL 2.6, HL 0.56, HW 0.63, CI 113, ML 0.24, MI 42, SL 0.31, SI 49, PW 0.35, AL 0.62. Characters of abdera-complex. Blade of mandible with 4 teeth: 2 preapical teeth and an apical fork of 2 spiniform teeth. Distal preapical tooth smaller than basal most preapical tooth and spiniform teeth. A small denticle is present at base of ventral apical tooth. Hairs on the dorsum of head posterior of frontal lobes and along upper scrobe margin are similar in shape to hairs on leading edge of scape. Leading edge of scape greatly expanded, forming a dorsoventrally flattened convex lamella with the widest portion in apical third. In profile, promesonotal dorsum convex and bluntly marginate laterally; propodeal dorsum convex anteriorly, sloping posteriorly to the declivity. Mesopleural hair organ conspicuous and set in a deep concave impression. Ground pilosity of dorsum of head posterior to frontal lobes consisting of rows of spatulate to spoon-shaped hairs. Erect hairs absent from head, alitrunk, and petiole. Hairs on gaster clavate. Head, alitrunk and petiole reticulate-punctate. Pleurae and sides of propodeum smooth except for peripheral punctures, which are most prominent on dorsal margin. Postpetiolar disc finely longitudinally costulate-punctulate. In profile the petiole with a well developed spongiform lamella. Postpetiole with well developed lateral and ventral spongiform lobes. Basigastral costulae well developed and sharply defined, extending across the basal third of gastral tergite, remainder of gaster more or less smooth and shiny. Propodeal teeth a blunt triangle and incorporated in the infradental lamellae. Infradental lamellae a narrow strip. Color pale orange-brown. PARATYPE WORKER TL 2.4 - 2.5, HL 0.53 - 0.55, HW 0.61 - 0.63, CI 110 - 118, ML 0.23 - 0.26, MI 44 - 47, SL 0.27 - 0.30, SI 44 - 49, PW 0.33 - 0.37, AL 0.58 - 0.61 (4 measured). As holotype. Holotype worker, Madagascar: Prov. Toamasina, F.C. Sandranantitra, 18 deg. 02.9 min. S, 49 deg. 05.5 min. E, 450 m, 18-21.i.1999, sifted litter (leaf mold, rotten wood) #101 (13)-1 (H.J. Ratsirarson) (MCZ). Paratypes. 2 worker with same data as holotype; 2 workers with same data as holotype but coded #101 (14)-1 (BMNH, SAM). S. heliani is distinguished from other species in the arnoldi-group by the absence of hairs on the dorsum of head posterior of frontal lobes and along upper scrobe margin that are similar in shape to hairs on leading edge of scape. Strumigenys levana Fisher sp. n. HOLOTYPE WORKER. TL 1.6, HL 0.37, HW 0.36, CI 95, ML 0.16, MI 43, SL 0.22, SI 62, PW 0.20, AL 0.41. Characters of lutron-complex. Mandible blade narrow, linear, outcurved, and armed apically with a fork of 2 spiniform teeth of which the upper is the longer. No intercalary denticles present between the apical fork teeth. Preapical dentition consisting of a single long spiniform tooth at about the apical third of the length present on both blades. Right mandible with a short tooth on the margin between the spiniform preapical tooth and the upper tooth of the apical fork, left mandible without such a tooth. Preocular lamina broad, projecting below the antennal insertion. Anterior clypeal margin with broad spoon-shaped hairs directed dorsally. Dorsum of head behind clypeus reticulate-punctate and with numerous broadly scale-like to spoon-shaped hairs on anterior two-thirds. Dorsum of head with a transverse row of 4 hairs close to the occipital margin. Upper scrobe margin with a continuous row of scale-like to spoon-shaped hairs. Hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Eye very small, with 3 ommatidia in total and situated just above the ventral scrobe margin. Antenna with 4 segments. Leading edge of scape a dorsoventrally flattened convex lamella with a row of projecting scale-like to spoon-shaped hairs. In profile, the promesonotum slightly convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Propodeal teeth very short, mostly incorporated in the infradental lamellae, with only a small point projecting. Sides of alitrunk smooth to superficially reticulate-punctate. Pronotal disc with distinct longitudinal costulae and not sculptured as posterior dorsum of head. In between costulae, pronotum smooth or with fine punctulate sculpture; remainder of dorsal alitrunk and at least the upper half of the propodeal declivity reticulate-punctate to alveolate. Pronotal humerus without a laterally projecting hair. Mesonotum with 2 pairs of erect hairs. Ground-pilosity of dorsal alitrunk consisting of scattered small erect hairs. Dorsal surface of petiole node with faint reticulate-punctate sculpture that is almost effaced; the postpetiole glassy smooth. Petiole, postpetiole and gaster with clavate hairs. In profile the petiole with a well developed spongiform lamella. Postpetiole with well developed lateral and ventral spongiform lobes. Base of first gastral tergite with fine costulae radiating on each side of a broad central clear area, remainder of gaster more or less smooth and shiny. Color dull yellow to pale brown. PARATYPE WORKER TL 1.6 - 1.7, HL 0.38 - 0.39, HW 0.34 - 0.35, CI 88 - 91, ML 0.17 - 0.18, MI 43 - 47, SL 0.21 - 0.23, SI 62 - 66, PW 0.20 - 0.21, AL 0.39 - 0.41 (5 measured). As holotype. Holotype worker, Madagascar: Prov. Toamasina, F.C. Sandranantitra, 18 deg. 02.9 min. S, 49 deg. 05.5 min. E, 450 m, 21-24.i.1999, sifted litter (leaf mold, rotten wood) #102 (26)-3 (H.J. Ratsirarson) (MCZ). Paratypes. 8 worker same data as holotype but coded (21)-1, (20)-2, (25)-3, (6)-3, (8)-3 (BMNH, SAM). Non-paratypic material examined. Madagascar: Andranobé, Route d'Andriamena, ca. 25 km W Morarano Sud ca 1250 m (A. Peyrieras); F.C. Andriantantely 530 m (H.J. Ratsirarson). Measurements of this material extends the range shown by the type-series: HL 0.39 - 0.42, HW 0.35 - 0.38, CI 91, ML 0.16 - 0.18, MI 41 - 42, SL 0.24, SI 63 - 68 (2 measured). S. levana is distinguished from other species in the arnoldi-group by the presence of 4 antennal segments, distinct longitudinal costulae on the pronotal disc, and pronotal humerus without a laterally projecting hair. The absence of laterally projecting hairs on the pronotal humus, and the presence of a transverse row of 4 hairs close to the occipital margin also help identify this species. Strumigenys lutron Fisher sp. n. HOLOTYPE. TL 1.6, HL 0.39, HW 0.38, CI 98, ML 0.14, MI 36, SL 0.20, SI 53, PW 0.23, AL 0.42. Characters of lutron-complex. Mandible blade narrow, linear, outcurved, and armed apically with a fork of 2 spiniform teeth of which the upper is the longer. No intercalary denticles present between the apical fork teeth. Preapical dentition consisting of a single long spiniform tooth at about the apical third of the length present on both blades. Right mandible with a short tooth on the margin between the spiniform preapical tooth and the upper tooth of the apical fork, left mandible with at most a denticle. Anterior clypeal margin broad, projecting beyond the mandibular bases on each side, with a feeble median impression and with numerous small spatulate to spoon-shaped hairs which are curved towards the midline. Lateral margin of clypeus short. Preocular lamina broad, projecting below the antennal insertion. Median portion of clypeus broad, finely punctulate and with scale-like to spoon-shaped hairs present. Dorsum of head behind clypeus reticulate-punctate and with numerous broadly scale-like to spoon-shaped hairs on anterior two-thirds. Outer margin of frontal lobe and upper scrobe margin with a continuous row of scale-like to spoon-shaped hairs. Hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Eye very small, with 3 ommatidia in total and situated just above the ventral scrobe margin. Antenna with 4 segments. Leading edge of the scape a dorsoventrally flattened convex lamella with a row of projecting scale-like to spoon-shaped hairs. Dorsum of head with a transverse row of 4 hairs close to the occipital margin. Pronotal humerus without a laterally projecting erect hair. Mesonotum with a pair of hairs on anterior margin (can be warn). In profile, the promesonotum slightly convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Propodeal teeth very short, mostly incorporated in the infradental lamellae, with only a small point projecting. Sides of alitrunk smooth to superficially reticulate-punctate. Dorsal alitrunk and at least the upper half of the propodeal declivity reticulate-punctate, the punctures more strongly defined and denser on the pronotum than on the propodeum, where they may be superficial. Pronotal humerus without a straight clavate hair. Anterior margin of mesonotum with a pair of short, filiform standing hairs. Ground-pilosity of dorsal alitrunk consisting of numerous small appressed hairs. In profile the petiole with a well developed spongiform lamella. Dorsal surface of petiole node finely punctate to reticulate, the postpetiole smooth. Petiole, postpetiole and gaster with short simple to narrowly clavate hairs. Color dull yellow to pale brown. PARATYPE WORKERS. TL 1.6 - 1.7, HL 0.39 - 0.41, HW 0.36 - 0.38, CI 92 - 96, ML 0.13 - 0.15, MI 33 - 39, SL 0.19 - 0.21, SI 52 - 57, PW 0.22 - 0.24, AL 0.41 - 0.45 (6 measured). As holotype. Holotype worker. Madagascar: Prov. Toamasina, S.F. Tampolo; 10 km NNE Fenoarivo Atn., 17 deg. 17 min. S, 49 deg. 26 min. E, 10 m, 4.iv.1997, sifted litter (leaf mold, rotten wood), littoral rainforest #1342 (49)-1 (B. L. Fisher) (MCZ). Paratypes. 6 workers as holotype but coded (21)-2, (34)-1, (36)-3, (42)-2, (47)-3 (BMNH, SAM). Non-paratypic material examined. Madagascar: 2.7 km WNW Ste. Luce 20 m (B. L. Fisher); Mandena, 8.4 km NNE Tolagnaro 20 m (B.L.Fisher); Forêt de Petriky, 12.5 km W Tolagnaro 10 m (B.L.Fisher). Measurements of this material extends the range shown by the type-series: HL 0.39 - 0.40, HW 0.38, CI 96 - 98, ML 0.15, MI 38 - 39, SL 0.20 - 0.21, SI 52 - 55 (2 measured). S. lutron is immediately separated from other members of the arnoldi-group by having 4 antennal segments, pronotal humeri without a projecting hair, and pronotal disk with densely reticulate punctate sculpture and without distinct longitudinal costulae. Strumigenys manga Fisher sp. n. HOLOTYPE WORKER. TL 2.4, HL 0.56, HW 0.49, CI 88, ML 0.22, MI 40, SL 0.26, SI 53, PW 0.29, AL 0.63. Characters of abdera-complex. Blade of mandible with 3 long teeth: 1 preapical tooth and an apical fork of 2 spiniform teeth; left blade of mandible with a small denticle and right mandible with a small tooth between preapical tooth and apex. Cephalic dorsum posterior of clypeal margin and upper scrobe margin with clavate to spoon-shaped hairs that are distinctly narrower than the hairs on leading edge of scape. Cephalic dorsum with a transverse row of 4 erect, short clavate hairs close to the occipital margin. Pronotal humerus with a projecting stiff hair; mesonotum with a short clavate hair on lateral anterior margin. In profile, outline of alitrunk convex in anterior half, more or less flat in posterior half; anterior mesonotal dorsum steeply descending to its posterior half. Propodeal dorsum more or less flat and meeting the declivity in rounded angle without a noticeable cuticular tooth. In profile, spongiform lamella continuous along propodeal declivity and marginate medially, forming a triangular tooth at apex of declivity. Ventral spongiform tissue and lateral lobes well developed and conspicuous on petiole and postpetiole; petiolar lamella notched medially. Base of first gastral tergite with basal costulae arising on each side of a central clear area. Dorsal surfaces of petiole, postpetiole, and gaster with clavate standing hairs. Color brown. PARATYPE WORKERS. TL 2.5, HL 0.56 - 0.57, HW 0.51 - 0.52, CI 90 - 91, ML 0.22, MI 39, SL 0.30 SI 59 - 60, PW 0.30 - 0.31, AL 0.65 - 0.67 (2 measured). As holotype. Holotype worker, Madagascar: Forêt d’Ankazomivady, 29 km SSW Ambositra, 1700 m, 20 deg. 46 min. 36 sec. S, 47 deg. 9 min. 54 sec. E. 8 Jan 1998, disturbed forest, nest 3 cm below leaf-litter covered soil surface found by digging SAM#011226 (H. R. Robertson) (SAM). Paratypes. 2 worker and 1 queen (dealate) with same data as holotype (BMNH). S. manga is separated from the other species in the arnoldi-group with 6 antennal segments by the presence of an erect hair on the pronotal humerus and the anterolateral margin of mesonotum, and the shape of the alitrunk in profile which is convex anteriorly and more or less flat posteriorly. Strumigenys micrans Fisher sp. n. HOLOTYPE WORKER. TL 1.7, HL 0.41, HW 0.35, CI 86, ML 0.18, MI 44, SL 0.25, SI 71, PW 0.21, AL 0.42. Characters of lutron-complex. Mandible blade narrow, linear, outcurved, and armed apically with a fork of 2 spiniform teeth of which the upper is the longer. No intercalary denticles present between the apical fork teeth. Preapical dentition consisting of a single long spiniform tooth at about the apical third of the length present on both blades. Right mandible with a short tooth on the margin between the spiniform preapical tooth and the upper tooth of the apical fork, left mandible without such a tooth. Preocular lamina broad, projecting below the antennal insertion. Anterior clypeal margin with broad spoon-shaped hairs directed dorsally. Dorsum of head behind clypeus reticulate-punctate and with numerous decumbent to suberect spatulate to spoon-shaped hairs on anterior two-thirds. Dorsum of head with a transverse row of 4 clavate hairs close to the occipital margin. Upper scrobe margin with a continuous row of clavate to spoon-shaped hairs. Hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Eye very small, with 3 ommatidia in total and situated just above the ventral scrobe margin. Antenna with 4 segments. Leading edge of scape a dorsoventrally flattened convex lamella with a row of projecting spoon-shaped hairs. In profile, the promesonotum slightly convex; propodeal dorsum shallowly convex anteriorly, sloping slightly posteriorly before meeting the declivity in a blunt angle without a noticeable tooth; infradental lamellae a very narrow strip. Sides of alitrunk mostly smooth and shiny with weak longitudinal striolate sculpture on dorsal side or pronotum. Pronotal disc with longitudinal striolate and costulae sculpture. In between costulae, pronotum smooth or with fine punctulate sculpture; remainder of dorsal alitrunk and at least the upper half of the propodeal declivity reticulate-punctate. Pronotal humerus with a laterally projecting flagellate or looped hair. Mesonotum with 1 pair of erect hairs on anterior margin. Ground-pilosity of dorsal alitrunk consisting of a few scattered small suberect fine hairs. Dorsal surface of petiole node with faint reticulate-punctate sculpture that is almost effaced; the postpetiole glassy smooth. Petiole, postpetiole and gaster with clavate to remiform hairs. In profile the petiole with a well developed spongiform lamella. Postpetiole with well developed lateral and ventral spongiform lobes. Base of first gastral tergite with costulae radiating on each side of a broad central clear area, remainder of gaster smooth and shiny where clean. Color dull yellow to pale brown. Holotype worker, Madagascar: Prov. Toamasina, P.N. Mantadia 895 m 18 deg. 47.5 min. S, 48 deg. 25.6 min E, 25-28.xi.1998 sifted litter (leaf mold, rotten wood), rainforest #111 (20)-1 (H.J. Ratsirarson) (MCZ). S. micrans is distinguished from other species in the arnoldi-group by the presence of a laterally projecting flagellate or looped hairs on the pronotal humerus and antenna with 4 segments. Strumigenys mola Fisher sp. n. HOLOTYPE WORKER. TL 1.9, HL 0.44, HW 0.41, CI 91, ML 0.16, MI 36, SL 0.23, SI 56, PW 0.25, AL 0.52. Characters of abdera-complex. Blade of mandible with 4 teeth: 1 long preapical tooth and a distal small preapical tooth (right blade) or denticle (left blade) and an apical fork of 2 spiniform teeth. Cephalic dorsum posterior of clypeal margin with spoon-shaped hairs on anterior two thirds; upper scrobe margin with spoon-shaped hairs. Posterior margin of vertex with a row of 4 erect, narrowly clavate hairs. Pronotal humerus without a projecting a hair; anterior margin of mesonotum with a pair of short standing hairs. In profile, promesonotum shallowly convex; metanotal groove a shallow concave depression. Propodeal dorsum convex anteriorly, sloping posteriorly to the declivity and posteriorly rounding into the sides. Propodeal dorsum meeting the declivity in a blunt angle without a noticeable tooth. In profile, spongiform lamella on propodeal declivity narrow, increasing in width at base of declivity. Ventral spongiform tissue well developed and conspicuous on petiole and postpetiole. Ventral lobe on petiole small. Base of first gastral tergite with a continuous row of well defined basal costulae, remainder of gaster smooth and shiny. Pilosity of postpetiole and gaster filiform to narrowly clavate. Color dull yellow to pale brown. PARATYPE WORKERS. TL 1.7 -1.9, HL 0.41 - 0.44, HW 0.38 - 0.40, CI 90 - 96, ML 0.15 - 0.16, MI 35 - 40, SL 0.19 - 0.24, SI 48 - 60, PW 0.23 - 0.25, AL 0.42 - 0.47 (6 measured). As holotype. Holotype worker, Madagascar: 43 km S Ambalavao, Res. Andringitra 22 deg. 14 min. S, 47 deg. 00 min. E, 825 m 5.x.1993, sifted litter (leaf mold, rotten wood), rainforest #747 (7)-7 (B.L.Fisher) (MCZ). Paratypes. 6 worker and 2 queens (dealate) with same data as holotype but coded (2)-11, (8)-12, (19)-12, (31)-8, (26)-12, (42)-15, (43)-11 (BMNH, SAM). Non-paratypic material examined. Madagascar: Ranomafana Nat. Park, Miaranony Forest 700 m (E. Rajeriarison); 7 km W Ranomafana 900 m (W.E. Steiner); 45 km S Ambalavao 785 m (B.L. Fisher); 9.0 km NE Ivohibe 900 m (S. Razafimandimby). Measurements of this material were within range of shown by the type-series (4 measured). Of the species known of this group which lack laterally projecting hairs on the pronotal humerus, and lack spoon-shaped or scale-like hairs on posterior third of the dorsum of the head, manga, is immediately identifiable by the presence of a pair of hairs on the anterior margin of the mesonotum. Strumigenys schuetzi Fisher sp. n. (Fig. 385) HOLOTYPE WORKER. TL 1.7, HL 0.40, HW 0.42, CI 105, ML 0.13, MI 32, SL 0.21, SI 50, PW 0.23, AL 0.41. Characters of schuetzi-complex. Mandible blade narrow, linear, outcurved, and armed apically with a fork of 2 long spiniform teeth of which the upper is the longer. No intercalary denticles present between the apical fork teeth. Preapical dentition consisting of a single long spiniform tooth at about the midlength of each blade. Anterior clypeal margin broad, projecting beyond the mandibular bases on each side and with numerous small spatulate to spoon-shaped hairs which are curved towards the midline. Lateral margin of clypeus short. Preocular lamina broad, projecting below the antennal insertion. Median portion of clypeus broad, finely punctulate and with scale-like to spoon-shaped appressed hairs present. Dorsum of head behind clypeus reticulate-punctate and with broadly scale-like to orbicular shaped hairs anterior of occipital corners. Dorsum of head without a transverse row of hairs close to the occipital margin. Row of scale-like to broad spoon-shaped hairs on upper scrobe margin not terminating at the posterior end with a more or less straight clavate hair. Eye very small, with 3 ommatidia in total and situated just above the ventral scrobe margin. Antenna with 4 segments. Leading edge of scape a dorsoventrally flattened convex lamella with a row of projecting broadly spoon-shaped hairs. Scape strongly back-curved, with a anteriorly projecting subbasal lobe at the bend, and apex of lobe with a projecting broad clavate, almost fan-like hair. In profile, the promesonotum slightly convex; propodeal dorsum shallowly convex anteriorly, sloping posteriorly to the declivity. Propodeal teeth very short, mostly incorporated in the infradental lamellae, with only a small point projecting; infradental lamellae a very narrow strip. Sides of alitrunk mostly smooth and shiny with weak peripheral punctures. Pronotal disk reticulate-punctate with longitudinal striolate and costulae sculpture, remainder of alitrunk dorsum reticulate punctate. Pronotal humerus with a laterally projecting straight clavate hair, remainder of alitrunk dorsum without erect hairs. Ground-pilosity of dorsal alitrunk consisting of scattered small suberect fine hairs. Dorsal surface of petiole node reticulate-punctate; the postpetiole more or less smooth. Petiole with a pair of broad clavate hairs; postpetiole and gaster with clavate to filiform hairs. In profile the petiole with a well developed spongiform lamella. Postpetiole with well developed lateral and ventral spongiform lobes. Base of first gastral tergite with costulae radiating on each side of a broad central clear area, remainder of gaster smooth and shiny where clean. Color pale brown. PARATYPE WORKER TL 1.6 - 1.8, HL 0.39 - 0.41, HW 0.41 - 0.42, CI 103 - 108, ML 0.13 - 0.15, MI 33 - 38, SL 0.21 - 0.22, SI 50 - 53, PW 0.24 - 0.25, AL 0.38 - 0.43 (4 measured). As holotype. Holotype worker, Madagascar: Prov. Antsiranana, R. S. Manongarivo, 10.8 km 229 deg. SW Antanambao, 400 m 13 deg. 57.7 min. S, 48 deg. 26.0, min. E, 8.xi.1998, sifted litter (leaf mold, rotten wood) #1996 (03)-2 (B.L. Fisher) (MCZ). Paratypes. 10 worker same data as holotype but coded #1996 (7)-2, (10)-2, (11)-2, (50)-4, (9)-2, (38)-3, (46)-4, (2)-2, (23)-1 (BMNH, SAM). Non-paratypic material examined. Madagascar: R. S. Manongarivo, 12.8 km SW Antanambao, 780 m (B.L. Fisher); R. S. Manongarivo, 14.5 km SW Antanambao, 1175 m (B.L. Fisher). Measurements of this material extends the range shown by the type-series: HL 0.40 - 0.45, HW 0.42 - 0.45, CI 99 - 103, ML 0.14 - 0.16, MI 32 - 35, SL 0.24, SI 54 - 56 (3 measured). S. schuetzi is distinguished from other species in the arnoldi-group by the presence of a laterally projecting straight clavate hair on the pronotal humerus, antenna with 4 segments, and mandible blade with only one preapical tooth, set in the midlength of blade. The upper scrobe margin with broadly spoon-shaped hairs that do not terminate at the posterior end with a more or less straight clavate hair also help distinguish this species. Strumigenys toma Fisher sp. n. (Fig. 386) HOLOTYPE WORKER. TL 1.7, HL 0.42, HW 0.38, CI 91, ML 0.12, MI 27, SL 0.21, SI 56, PW 0.25, AL 0.46. Characters of alapa-complex. Blade of mandible with 3 teeth: 1 preapical tooth and an apical fork of 2 spiniform teeth. Anterolateral margin of clypeus with a spoon-shaped hair curved medially that is larger than hairs found on anterior margin of clypeus. In dorsal view, cephalic dorsum with broadly scale-like to orbicular shaped hairs on anterior two thirds, extending on to vertex, posterior of posterior end of upper scrobe margin. Cephalic dorsum posterior of clypeal margin with broadly scale-like to orbicular shaped hairs; hairs present posterior of posterior end of upper scrobe margin. Upper scrobe margin with broadly scale-like hairs. Pronotal humerus without a projecting hair; mesonotum without standing hairs. In profile, pronotal dorsum shallowly convex; mesonotum with a shallowly concave depression. Propodeal dorsum more or less flat anteriorly, sloping slightly posteriorly before meeting the declivity in a blunt angle without a noticeable tooth. Ventral spongiform tissue well developed and conspicuous on propodeum, petiole and postpetiole. In profile, spongiform lamella on propodeal declivity broad, approximately half the width of ventral spongiform curtain on petiole. Disc of postpetiole covered by a densely punctulate film of spongiform tissue. Basigastral costulae short, sparse and not sharply defined; gastral tergite covered in punctulate- to granulate-reticulate sculpture, at least on lateral margins. Base of first gastral tergite with few basal costulae. Hairs on postpetiole and gaster filiform. Color pale brown. PARATYPE WORKERS. TL 0.42, HL 0.39, HW 0.39, CI 93, ML 0.12, MI 28, SL 0.20, SI 52, PW 0.25, AL 0.48 (1 measured). As holotype. Holotype worker, Madagascar: Prov. Fianarantsoa, 28 km SSW Ambositra, Ankazomivady, 20 deg. 46.5 min. S, 47 deg. 10.1 min. E, 1670 m, 11.i.1998, sifted litter, grassland, #1620 (25)-2 (B.L. Fisher) (MCZ). Paratypes. 1 worker with same data as holotype (BMNH). S. toma forms a close species pair with dolabra, within the arnoldi-group. Characters distinguishing toma are discussed under dolabra. dexis-group DIAGNOSIS OF WORKER Mandible in full-face view short (MI range 17 - 33), with broadly rounded prominent basal-external angle visible; the dorsum proximal of the basalmost tooth distinctly concave, the concave area margined distally by a rim or carina that traverses the blade. Blade of mandible broad basally and tapering strikingly towards the apex in full-face view, leaving a subovate gap between the inner margins of the blades distal of the basal lamella. Dentition. Left mandible with 5 teeth and denticles in total, right mandible with 6. Dentition of the mandibles is asymmetrical in the group. In all species the left mandible has 3 long teeth (second or third from the base is the longest) followed by either a denticle and a smaller tooth or 2 denticles that share a common base, and are located ventral to the third tooth. The right mandible has a long basal tooth followed by a much smaller second tooth; these are followed by two more long teeth (the third from the base longer than the fourth) and the fourth is subtended by a pair of denticles, or a denticle and a short tooth, below the base of the fourth tooth. Therefore in full-face view the left mandible has 3 long or spiniform teeth and the right has 4, the apical denticles not being visible in this aspect. This group shows a morphocline of shortening mandibles. At the longest (sylvaini, MI 28 - 31; carolinae, MI 29 - 33) the species are more or less "ordinary" Strumigenys, but at the other end the mandibles are shorter and more powerfully constructed (dexis, MI 17 - 20), closely resembling short-mandibulate groups of Pyramica. However, even at this end of the morphocline the species retain the apomorphies of Strumigenys. It appears that the members of the group are evolving to fill the "powerfully short-mandibulate Pyramica" niche, which is almost empty in the Malagasy region. Leading edge of scape a dorsoventrally flattened convex lamella. Upper scrobe margins in full-face view widely divergent behind the frontal lobes. Ventrolateral margin of head without trace of a preocular notch, the margin continuos in from of the eye. Ventral surface of ahead without a preocular transverse groove but postbuccal groove is distinct. Promesonotum flat and bluntly marginate laterally (rounded in carolinae). Glands. Gland of scape visible as an elongate patch of pale tissue near the apex of the ventral scape. Apicofemoral gland absent to well developed; decreasing in size from hind femora where it is easily visible to the profemora where it is minute to absent. Absent on all femora of sylvaini and wardi. Apicotibial gland bola absent on all tibia of workers (sylvaini, wardi), present on hind tibia (peyrierasi, gorgon, dexis, coveri), or present on hind and fortibia (alperti, carolinae). Gland at base of fortibial spur conspicuous. Apicotarsal glands not visible. Mesopleural hair-filled gland visible and set in a narrow circular notch. Spongiform appendages of petiole well developed into a ventral curtain; lateral lobes present. Postpetiole with lateral and ventral lobes. Infradental lamella of propodeum usually well developed into a wide strip below the triangular propodeal spines (narrow in 2 species). Pilosity. Head with broadly spatulate to spoon-shaped hairs present on mandibles, lateral clypeal margins (curved anteriorly), upper scrobe margins (curved anteriorly) and leading edges of scapes (curved toward scape apex); entire body lacking flagellate hairs. Dorsal surfaces of mandibles with elongate spatulate hairs that are directed towards the midline. Sculpture. Within the dexis-group two forms of basic sculpture are developed. The first, (seen in the sylvaini-complex), is that predominant in the tribe as a whole: fine dense reticulate-punctate to reticulate-granulate sculpture that blankets the entire dorsum of the head and the alitrunk (alitrunk not reticulate-punctate in carolinae), rendering them opaque. The balance of species (dexis-complex), the sculpture is quite different. On the dorsum of the head there are scattered punctures that are separated by areas of smooth unsculptured cuticle. On the dorsal alitrunk the sculpture is either the same as the head or even more sparsely punctate with more extensive smooth areas. The structure of the mandibles and their dentition is immediately diagnostic of the dexis-group. The presence of a rim or carina that traverse a basal concavity of the mandibles and the asymmetric mandibles (the left mandible with 3 long or spiniform teeth, including preapical and apical, and the right with 4 such teeth) are apomorphies for the group. Members of this group fall into two discrete complexes of related species. 1) dexis-complex (coveri, dexis, gorgon, peyrierasi, rabesoni) Dorsum of the head and promesonotum with scattered punctures separated by smooth, shining areas of cuticle. 2) sylvaini-complex (alperti, carolinae, sylvaini, wardi). Dorsum of the head and often the promesonotum with fine dense reticulate-punctate to reticulate-granulate sculpture; scattered punctures separated by smooth shiny areas never present on head and promesonotum. Strumigenys alperti Fisher sp. n. HOLOTYPE WORKER. TL 2.3, HL 0.60, HW 0.52, CI 87, ML 0.14, MI 23, SL 0.27, SI 52, PW 0.31, AL 0.64. Characters of sylvaini-complex. Lateral margins of clypeus, upper scrobe margins, and leading edges of scapes each fringed with a row of curved spoon-shaped hairs. Clypeal dorsum with short, anteriorly-directed spatulate hairs. Dorsum of head immediately behind clypeus with a transverse band of scale-like hairs, arranged in 3 - 4 rows, these hairs similar in size to those fringing the upper scrobe margins. Similar but somewhat more spoon-shaped hairs are also numerous on the dorsal surfaces of the occipital lobes, but they are absent from the median posterodorsal area of the head. There are no standing hairs of any description on the head, alitrunk, postpetiole or first gastral tergite. Eye conspicuous, with 4 - 5 ommatidia in the longest row. Promesonotal dorsum finely and densely reticulate-punctate, the sculpture fading posteriorly on the propodeal dorsum. Pleurae glassy smooth. Petiole node broader than long in dorsal view, finely reticulate-punctate and with several pairs of posteriorly curved decumbent spatulate hairs. Disc of postpetiole completely surrounded by spongiform tissue; disc with weak longitudinal striolate sculpture on each side of a smooth median strip. Basigastral costulae moderately developed, extending for some distance onto the first gastral tergite. PARATYPE WORKERS. TL 2.4, HL 0.60 - 0.61, HW 0.52 - 0.54, CI 85 - 89, ML 0.14 - 0.15, MI 23 - 25, SL 0.27 - 0.28, SI 50 - 54, PW 0.31 - 0.32, AL 0.66 - 0.68 (2 measured). As holotype. Holotype worker, Madagascar: 17 km W Andapa, Res. d'Anjanaharibe Sud, 875 m, 2.xi.1994, 14 deg. 45 min. 27.9 sec. S, 49 deg. 30 min. 36.7 sec. E, primary rainforest, nest in log under moss, 543.12969w (G. D. Alpert) (MCZ). Paratypes. 1 worker and 1 queen (dealate) with same data as holotype but 543.12968q; 1 worker (gaster missing) with same data but 543.13484w (MCZ, BMNH). Non-paratypic material examined. Madagascar: 6.9 km NE Ambanizana, 825 m (B. L. Fisher); 9.2 km WSW Befingotra, Res. Anjanaharibe-Sud, 1200 m (B. L. Fisher); 6.5 km SSW Befingotra, Res. Anjanaharibe-Sud 875 m (B. L. Fisher). The non-paratypic material shows greater size-variation than the type-series alone: HL 0.60 - 0.66, HW 0.51 - 0.58, CI 85 - 89, ML 0.15 - 0.17, MI 24 - 27, but otherwise matches all the critical diagnostic characters. S. alperti is immediately separated from all other members of the group by its unique possession of a transverse band of scale-like hairs, made up of 4 - 5 rows, on the cephalic dorsum immediately behind the clypeus. S. alperti can be separated from carolinae by the presence of reticulate-punctate sculpture on the promesonotum. Otherwise alperti and carolinae can be separated from other members of the sylvaini-complex by the following characters. alperti and carolinae 1) Erect short simple hairs entirely absent from dorsal surfaces of head, alitrunk, waist segments and first gastral tergite. 2) Head dorsolaterally with broad scale-like hairs present. 3) Disc of postpetiole completely surrounded by spongiform tissue in dorsal view. wardi and sylvaini 1) Erect short simple hairs present on dorsal surfaces of head, alitrunk, waist segments and first gastral tergite. 2)Head dorsolaterally without scale-like hairs. 3) Disc of postpetiole not surrounded by spongiform tissue in dorsal view, with anterolateral angles and anterior halves of sides free. Strumigenys carolinae Fisher sp. n. HOLOTYPE WORKER TL 2.2, HL 0.55, HW 0.47, CI 85, ML 0.17, MI 31, SL 0.26, SI 56, PW 0.27, AL 0.57. Characters of sylvaini-complex. Entire dorsum of head blanketed with fine, dense reticulate-punctate to reticulate-granulate sculpture. Clypeal dorsum with short, anteriorly-directed spatulate hairs. Spoon-shaped hairs are numerous on the dorsal surfaces of the occipital lobes, but they are absent from the median posterodorsal area of the head and from immediately behind clypeus. There are no standing hairs of any description on the head, alitrunk, postpetiole or first gastral tergite. Eye conspicuous, with 4 - 5 ommatidia in the longest row. Promesonotal dorsum mostly smooth. Promesonotal humeral angles rounded. Mesopleural gland large and circular. Petiole node broader than long in dorsal view, and with several pairs of posteriorly curved decumbent spatulate hairs. Disc of postpetiole completely surrounded by spongiform tissue; disc with a mostly smooth dorsal disk. Basigastral costulae moderately developed, extending for some distance onto the first gastral tergite. PARATYPE WORKER TL 2.2 - 2.4, HL 0.55 - 0.58, HW 0.46 - 0.49, CI 81 - 87, ML 0.16 - 0.18, MI 29 - 32, SL 0.26 - 0.27, SI 55 - 57, PW 0.26 - 0.30, AL 0.55 - 0.62 (4 measured). As holotype. Holotype worker, Madagascar: Prov. Antsiranana, R.S. Manongarivo, 10.8 km 229 deg. SW Antanambao, 400 m 13 deg. 57.7 min. S, 48 deg. 26.0 min. E, 8.xi.1998, sifted litter (leaf mold, rotten wood), rainforest #1996 (40)-2 (B.L. Fisher) (MCZ). Paratypes. 36 worker 3 queens (dealate) same data as holotype but coded (13)-1, (18)-1, (32)-1, (35)-1, (35)-2, (35)-3, (38)-1, (38)-2, (42)-2, (44)-4, (45)-1, (46)-1, (46)-2, (49)-1, (50)-6, (51)-1, (55)-2, (56)-7, (70)-2 (BMNH, SAM). Non-paratypic material examined. Madagascar: R.S. Manongarivo, 12.8 km 228 deg. SW Antanambao, 780 m (B.L. Fisher); R.S. Manongarivo, 14.5 km 220 deg. SW Antanambao, 1175 m (B.L. Fisher); Nossi Be Island (P. Saranya). Measurements of this material extends the range shown by the type-series: HL 0.58 - 0.65, HW 0.46 - 0.52, CI 79 - 83, ML 0.18 - 0.21, MI 30 - 33, SL 0.28 - 0.30, SI 56 - 59 (6 measured). S. carolinae is immediately separated from all other members of the group by its unique possession of: 1) rounded promesonotal humeral angles. 2) dense reticulate-punctate to reticulate-granulate sculpture present on the dorsum of the head but absent from promesonotum. Strumigenys coveri Fisher sp. n. HOLOTYPE WORKER. TL 2.4, HL 0.63, HW 0.51, CI 81, ML 0.14, MI 22, SL 0.28, SI 55, PW 0.31, AL 0.68. Characters of dexis-complex. With head in full-face view the dorsal surfaces of the occipital lobes with broad spoon-shaped hairs similar in shape and size to those projecting from the upper scrobe margins; these hairs occupying a longitudinal strip on each side from the apices of the upper scrobe margins to the apices of the occipital lobes, but absent from the vertex proper. Eye with 12 - 13 ommatidia in total. Punctures on vertex small and faint, widely spaced, the distance between punctures greater than the diameter of the punctures. Punctate sculpture sparse and faint on dorsal promesonotum, almost effaced. Pronotum in dorsal view relatively narrow, about as broad as long, decidedly not conspicuously broader than long. Dorsum of petiole node (discounting spongiform tissue) longer than broad. Disc of postpetiole smooth. Basigastral costulae weakly developed and inconspicuous, sparse, faint and short. Standing hairs completely absent from dorsal surfaces of body. PARATYPE WORKERS. TL 2.4, HL 0.63 - 0.64, HW 0.51 - 0.52, CI 80 - 83, ML 0.14, MI 22, SL 0.28 - 0.29, SI 55 - 56, PW 0.30 - 0.31, AL 0.66 - 0.68 (2 measured). As holotype but number of ommatidia in eye varies from 11 to 13. Holotype worker, Madagascar: 1 km W Andampibe, Cap Masoala, 125 m, 2.xii.1993, 15 deg. 51 min. 37 sec. S, 50 deg. 10 min. 53.4 sec. E, lowland rainforest, Winkler app. 259.3308w (Alpert et al.) (MCZ). Paratypes. 1 worker with same data as holotype; 2 workers (one with head missing) 2 km W Andampibe, Cap Masoala, 125 m, 1.xii.1993, 15 deg. 41 min. 25 sec. S, 50 deg. 10 min. 10 sec. E, lowland rainforest, Winkler app. 238.3325w (Alpert et al.) (SAM, BMNH). Non-paratypic material examined. Madagascar: 6.3 km S Ambanizana, Andranobe, 25 m, (B. L. Fisher); 5.3 km SSE Ambanizana, Andranobe, 425 m (B. L. Fisher); Prov. Toamasina, F.C. Didy 960 m (H. J. Ratsirarson). Measurements of this material extends the range shown by the type-series: HL 0.62 - 0.68, HW 0.51 - 0.55, CI 80 - 85, ML 0.14 - 0.17, MI 22 - 26. Within the dexis-complex coveri is immediately separated from all other members (dexis, gorgon, peyrierasi, rabesoni) by the condition of the petiole node. In dorsal view the cuticular area of the node (discounting the lateral lobes and posterior collar) is at least as long as broad, and usually distinctly longer than broad in coveri, while in the other species it is very obviously broader than long. The basigastral costulae are very short with a few feeble longer costulae in coveri, while in the other species, costulae well developed and numerous. Further differentiating characters are noted under the other species of the complex. Strumigenys dexis Fisher sp. n. HOLOTYPE WORKER. TL 2.4, HL 0.66, HW 0.57, CI 88, ML 0.12, MI 18, SL 0.29, SI 51, PW 0.36, AL 0.68. Characters of dexis-complex. Transverse edge of the depressed proximodorsal area of mandible with a short row of curved spoon-shaped hairs approximately the same as those fringing the upper scrobe margin. Each labral lobe terminates anteriorly in a broad fan-shaped lamella of thin translucent cuticle and a short range-finder hair mesad of fan-like lamella; range-finder hairs often difficult to see. Clypeal dorsum with minute appressed hairs, the lateral margins with a short row of anteriorly curved large spoon-shaped hairs. Upper scrobe margins in full-face view with a continuous row of anteriorly curved spoon-shaped hairs that are similar to those on the leading edge of the scape; the row ends at the apex of the scrobe and does not extend onto the side of the occipital lobe. Eye with 7 ommatidia in total. Dorsum of head without standing hairs of any description but with scattered minute flattened appressed hairs present. Area of cuticle within antennal scrobe densely reticulate-punctate except for extreme posterior portion which is superficially reticulate to smooth. Dorsum of head behind clypeus with separated shallow punctures, the spaces between them shining; ventral surface of head unsculptured. Pronotum in dorsal view with strongly convex sides, appearing very short and broad. Flattened dorsum of pronotum sculptured as vertex; pleurae and sides of propodeum smooth and shining; propodeal declivity with a band of fine punctate sculpture between the teeth. Infradental lamella of propodeum broad and sinuate, apices of propodeal teeth f