March, 1914] WhEELER : Ants FROM HiDALGO, MEXICO. 47 



high and transverse, with long, concave anterior and short, abrupt, posterior 

 slope, its border entire and evenly rounded. Postpetiole twice as broad as the 

 petiole, decidedly broader than long, with each side produced in the middle as 

 a distinct, pointed conule. Gaster elliptical, much smaller than the head. Legs 

 rather long and slender. 



Body shining; clypeus and anterior half of head rather coarsely longi- 

 tudinally rugose, the spaces between the rugae feebly reticulate. Mandibles and 

 posterior half of head with scattered, piligerous punctures. Thorax, pedicel 

 and gaster also with similar punctures, but the pleurae irregularly rugulose and 

 the epinotum subopaque, densely and superficially punctate. 



Hairs yellowish, erect or suberect, delicate, moderately long and abundant, 

 covering the body, scapes and legs. 



Ferruginous ; borders of mandibles, sides of the clypeus, the median longi- 

 tudinal groove of the head, the mesonotum, epinotum, pedicel and gaster dark 

 brown or blackish. 



Mediae. — Length 2.5-3.5 mm. 



Representing a series of intermediates between the soldier and worker in 

 the size and sculpture of the head and in the size and shape of the body. 



Worker. — Length 2-2.5 rnm. 



Head, excluding the mandibles, subrectangular, as broad as long. Man- 

 dibles with 5 or 6 denticles. Clypeus rather convex, with entire anterior 

 border. Eyes just in front of the middle of the head, moderately convex. 

 Antennal scapes scarcely surpassing the posterior corners of the head. Thorax 

 like that of the soldier. Postpetiole nearly as long as broad, its sides in the 

 middle distinctly angular, but not produced or conulate. 



Shining; anterior half of head and the whole thorax subopaque and densely 

 punctate, the cheeks and front also longitudinally rugose ; pronotum smooth 

 and shining above. 



Pilosity similar to that of the soldier but shorter. 



Black; antennje and legs piceous; mandibles, bases of funictili, tarsi and 

 articulations of legs yellowish. 



Female. — Length 5.5-6 mm. 



Head rectangular, not longer than broad. Eyes rather large and convex. 

 Thorax of the usual shape, with flat mesonotum and scutellum ; epinotum slop- 

 ing, without distinct base and declivity, armed with two short, acute teeth, 

 which are very broad at their bases. Petiole and postpetiole like those of the 

 soldier. Gaster broadly elliptical. Wings very long (10 mm.). 



Shining and with sparse, minute, piligerous punctures; mandibles more 

 coarsely punctate ; sides of clypeus and anterior ^ of head subopaque, longi- 

 tudinally rugose. 



Pilosity much as in the soldier but more appressed on the thorax and 

 gaster. 



Dark brown ; mandibles, except their borders, which are black, clypeus, 

 cheeks, pronotum, pleurae, antennae and legs reddish or ferruginous. Wings 

 gray, with pale brown veins and stigma. 



