392 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 1890. 



which is twice as long as the 7th joint. Maxillary palpi o-jointed, 

 labial 3-jointed. Mandibles armed with 4 stout teeth. Epistome 

 strongly vaulted, furnished with 2 longitudinal ridges, it forms 

 posteriorly a boss between the frontal ridges, which are short, but 

 fairly high. Frontal area narrow and deep ; frontal groove short. 

 Eyes placed rather in front of the sides of the head. Thorax con- 

 stricted behind the mesonotum ; pronotum and mesonotum moderately 

 vaulted, the latter rather the more so ; the former more flattened 

 and narrower than in Phcidole. Metanotum armed with 2 stout spines, 

 elegantly curved forward. The first knot of pedicle with a rather 

 long and anteriorly broad petiole ; this petiole, somewhat concave 

 above and convex beneath, is furnished beneath, anteriorly, with a 

 small tooth, and posteriorly with a somewhat small, conical, squami- 

 form protuberance. The second knot is very low, broader than long, 

 rounded anteriorly, and broadly attached posteriorly to the abdomen. 

 Abdomen small; seen from above it is narrow in front, and feebly 

 enlarged to the end of the first segment. The other segments appear 

 only as a small cone projecting beyond the first segment. Side vieAV, 

 the abdomen is triangular, the sides of the triangle are somewhat 

 convex. The profile forms an isosceles triangle, of which the base, 

 formed by the flattened upper surface of the abdomen, is long-er than 

 the two sides. The summit of the triangle (more properly of the 

 cone), is almost in the middle of the underside of the first segment, 

 which of itself constitutes nearly the whole ventral (as it does the 

 dorsal) surface. Erect hairs of the bod}^ toothed and blunt as in the 

 genus Li'j)totJ>ora,r. 



This singular ant is closely allied to the genus PJteidolc, but there 

 was no " soldier" among the specimens sent me by Mr. Wroughton . 

 Otherwise the head is smaller, and the club of the antennae recalls 

 only that of certain aberrant species. The species of Phcidole have 

 ] 2-jointed antennae, except P/i. quadrispfyosa, which has 11. However, 

 the singular form of the abdomen, the form of the epistome, and the 

 low and narrow pronotum isolate this insect sufficiently to found on it 

 a genus. All the £ seem to be the same size. 



Trigonogastcr reeUtrvispinosus, n. sp. 

 $ Length about 2 mm. Characters of the genus. Head nearly 

 square, slightly longer than broad, hollowed posteriorly, the sides 



