HOLOTYPE WORKER. TL 2.6, HL 0.76, HW 0.64, CI 85, ML 0.42, MI 55, SL 0.52, SI 81, PW 0.33, AL 0.76. Characters of chilo-complex. Mandibles almost straight and at full closure parallel. Apical fork of mandible subtended by a third, shorter spiniform tooth, the fork effectively 3 - dentate; without intercalary teeth or denticles. Preapical teeth absent but a small spiniform denticle may occur immediately proximal of apicodorsal tooth on right mandible. Upper scrobe margin ends, or at least becomes extremely indistinct, at about the level of the eye; when viewed in profile, upper scrobe margin extends posteriorly across dorsal apex of vertical preocular groove of side of head; preocular groove meets and is interrupted by the upper scrobe margin before reaching the cephalic dorsum. Eye large, convex, and plainly visible in full-face view. Scape long and slender, approximately straight, the leading edge with a row of slender hairs which are slightly flattened or spoonshaped apically. Cephalic dorsum densely clothed with curved spoon-shape ground-pilosity; the upper scrobe margin without a row of hairs. Cephalic dorsum with 6 simple standing hairs arranged in a transverse row close to the occipital margin. Dorsum of head reticulatepunctate. Pronotum without standing hairs. Mesonotum with two pairs of stout standing remiform to narrowly clavate hairs: a pair on anterior margin and a posteriorly situated pair. Propodeum with one pair of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on alitrunk as on head but sparser. With the alitrunk in profile the posterior portion of the mesonotum sharply depressed, the metanotal groove represented by a shallow impression. Pronotal humeri rounded. Lateral margin of posterior pronotum bluntly marginate. Anterior mesonotum with a narrow carina above the mesothoracic spiracle. Propodeal tooth long, slender, almost spiniform; propodeal 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 petiole weakly developed. Postpetiole with small but distinct lateral and ventral spongiform lobes. Basigastral costulae fine and superficial across base of gaster without a central clear area; gaster smooth and shiny where clean. Dorsal surfaces of petiole and postpetioje each with a pair of posteriorly projecting stout hairs; gaster with stout standing hairs which are weakly swollen apically. Colour dull yellow to light medium brown.
PARATYPE WORKERS. TL 2.9 - 3.1, HL 0.74 - 0.79, HW 0.62 - 0.67, CI 83 - 87, ML 0.40 - 0.43, MI 53 - 57, SL 0.50 - 0.55, SI 78 - 85, PW 0.32 - 0.35, AL 0.72 - 0.77 (8 measured). As holotype.
Holotype worker, Madagascar: Isalo Nat. Park, Ranohira Canion de Singe forest, 800 m., 22 ° 29 ' S, 45 ° 331 E, 17. ii. 1993, twig nest, # 1397 w (E. Rajeriarisori) (MCZ).
Paratypes. 10 workers with same data as holotype but coded: #. 13962,. 13965,. 13968,. 13970,. 13977 (BMNH, SAM).
NON-PARATYPIC MATERIAL EXAMINED. Madagascar: F. C. Didy 960 m. (H. J. Ratsirarson); 6 km. ESE Andasibe, 900 m. (P. S. Vhrd); Ranomafana (A. Kingman); Ranomafana (V. Roth); 7 km. W Ranomafana Nat. Park, 900 m. (WE. Steiner); Isalo Nat. Park (E. Rajeriarisori).
Measurements of this material extend the range shown by the type-series: HL 0.80 - 0.81, HW 0.66 - 0.73, CI 83 - 89, ML 0.43 - 0.46, MI 53 - 57, SL 0.54 - 0.57, SI 77 - 82 (3 measured).
Among the Malagasy species that have the mandibular apical fork subtended by a shorter third tooth ampyx is easily isolated by the following characters:
1 Upper scrobe margin ends, or at least becomes extremely indistinct, at about the level of the eye; when viewed in profile, upper scrobe margin extends posteriorly across dorsal apex of vertical preocular groove of side of head; preocular groove meets and is interrupted by the upper scrobe margin before reaching the cephalic dorsum.
2 Mesonotum with 2 pairs of erect hairs on anterior margin.
3 Cephalic dorsum with a transverse row of six erect hairs immediately in front of occipital
margin.
