— 236 — 



a rather deep groove. In profile the epinotuin is rounded, with 

 a scarcely perceptible angle between the base and declivity. Me- 

 tasternal angles sharp and compressed. Petiole with long pedun- 

 cle, a minute anteroventral tooth and a large, rounded , antero- 

 posteriorly compressed node, which has a deeply concave anterior 

 and straight and more abrupt posterior slope. Postpetiole broader 

 than the petiole, rounded above and slightly compressed antero- 

 pusteriojly; at its anteroventral border it has a low, rounded tu- 

 bercle instead of a tooth. 



Mandibles and clypeus subopaque, very minutely and indi- 

 stinctly punctate. Remainder of body smooth, shining and very 

 sparsely punctate. 



Hairs long, suberect, moderately abundant, yellow, covering 

 the body, legs and antennal scapes; pubescence confined to fu- 

 niculi. 



Piceous; mandibles, clypeus, cheeks, antennae, legs, border 

 of first and whole of the remaining gastric segments, reddish 

 yellow; neck, pleurte, epinotum and ventral portions of petiole and 

 postpetiole deep red. 



Described from four workers taken at Cordoba. This differs 

 from all the other described species of Megaloiiììjrme.r in its 

 very small stature, the structure of the pro-and mesonotum, and 

 especially in the mandibles, which somewhat resemble those of 

 Gnamptogenys and Leptogenys s. str and probably represent an 

 adaptation to feedingon soft-bodied insects, such as termites and 

 larv£e. It may be advisable to make M. silvestrii the type of 

 a new subgenus, but the various species of the genus are so 

 imperfectly known that I hesitate to do this. The workers of 

 the known species, except M. latreiUel Emery, which seems to 

 be synonymous with M bituberculatus J^'abr., may be identified 

 with the aid of the following table: 



1. Mandibles rather feeble and fiat, their blades minutely denti 

 culate, with only two teeth, which are apical; promesonotal suture not 

 impressed, very indistinct; color piceous, with yellow legs. Length 3.5-4 

 mm. Mexico silvestrii sp. nov. 



Mandibles more robust and convex, with large, subequal teeth; 

 promesonotal suture marked by a distinct impression 2 



2. Mandibles opaque^ striated, with 6 teeth; antennal club 4 — 

 jointed. Color testaceous yellow, legs paler. Length 4 -- 4.75 mm. Co- 

 sta Eica. , modestus Emery. 



