wheeler: ants collected in trinidad. 325 



34. Mycocepurus smithi Forel. S . — Diego Martin (Urich). 



35. Apterostigma wasmanni Forel. S . — Four Roads, Port of Spain 

 (Thaxter) ; " from fungus garden under a log." 



36. Apterostigma urichi Forel. U. — Caparo (Thaxter); "from 

 fungus garden under a log." 



37. Trachymyrmex urichi Forel. ^ . — Ariopita Valley (H. D. 

 Chapman); Gasparee Island (Thaxter). 



38. Trachymyrmex humilis, sp. nov. 



Worker. Length 2.2-2.5 mm. 



Mandibles rather long, with concave external borders, three large 

 apical and several smaller basal teeth. Head subrectangular, as 

 broad as long, with broadly and feebly excised posterior and rather 

 convex lateral borders and rounded posterior corners. Eyes moder- 

 ately convex. Clypeus short, with nearly straight, entire anterior 

 border. Expanded anterior lobes of frontal carinae moderately large, 

 rounded, not angular, posterior ridges diverging but not reaching the 

 posterior corners of the head. Praeorbital carinae straight, not curved 

 inward across the antennal scrobes, terminating a little behind the eyes. 

 Antennal scapes moderately stout, reaching a distance not exceeding 

 their greatest transverse diameter beyond the posterior corners of the 

 head. Joints 2-8 of the funiculi not longer than broad, two terminal 

 joints forming an indistinct club, the penultimate longer than broad 

 and half as long as the last joint. Thorax with the pro- and mesono- 

 tum rather convex and rounded in profile, the mesoepinotal constric- 

 tion short and deep. Inferior pronotal spines short, moderately 

 acute. Epinotum much higher than long, the base in profile very 

 convex anteriorly, sloping behind, broadly sulcate above, somewhat 

 longer than the declivity, the spines reduced to two teeth which are 

 only slightly longer than broad at their bases, directed upward, out- 

 ward, and backward. Petiole small, not longer than high, the node 

 feebly developed, acute in profile, with longer concave anterior and 

 short concave posterior slope. Postpetiole very large, more than twice 

 as broad as the petiole, as long as broad, broadest behind, with a 

 median semicircular impression at the posterior border; in profile 

 the node is very convex and high in front, the remaining dorsal surface 

 flattened. Gaster suboblong, with rounded anterior and posterior 

 corners, a little longer than broad, with straight, marginate sides, its 

 upper surface evenly and feebly convex, without any longitudinal 

 impressions. Legs moderately long. 



Mandibles shining, with a few very coarse, elongate punctures. 



