346 S. B. Buckley on North American Formicidse. 



Worker minor. Length 0.13 inch. — Differs little from worker ma- 

 jor, except in size ; the small workers are the most numerous. 

 Beneath stones in the vicinity of Philadelphia. 



60. Atta coloradensis, n. sp. 



Worker major. Length 0.23 inch. — Reddish -brown ; abdomen pi- 

 ceous aud sometimes part of the upper surface of the head and thorax ; 

 head large, subquadrate, posterior augles rounded, a channel extends 

 from the base of the clypeus over the top of the head to the base of the 

 occiput, which is emarginate ; eyes small, circular, lateral, about mid- 

 way of the head; antennae near the base of the clypeus; short, clavate; 

 mandibles brownish-black, short, small, curved inwards, acute ; under 

 .surface of the head not channeled ; prothorax J narrower than the 

 head, rounded at sides and above; mesothorax depressed a little, a 

 slight strangulation between it and the metathorax ; metathorax rounded 



Co / 



above and at the sides, and slopes gradually to the pedicle which is 

 long; front scale sub-wedge-shaped and smallest, posterior one nodose; 

 abdomen ovate; legs long, slender, whole surface sprinkled with gray 

 hairs aud rather smooth and shining. 



Worker minor. Length 0.13 ineh. — Whole upper surface piceous 

 or black, tibiae, tarsi and under surface of thorax pale yellow, under 

 surface of head and abdomen piceous tinged with pale yellow or red- 

 dish-brown ; head ovate, smooth, and rounded above, not emarginate ; 

 smooth and shining throughout, with few or no hairs; otherwise like 

 the worker major. 



Dwells in the ground near the Colorado river in Northern Texas. 



61. CEcodoma virginiana, n. sp. 



Worker. Length 0.11 inch. — Yellowish-red; head triangular, some- 

 what flattened above, its posterior angles not rounded and sides nearly 

 straight; eyes rather large, blackj prominent, lateral, aud about mid- 

 way of the head ; mandibles sub-triangular, acute ; antennae short, api- 

 cal joint long and enlarged ; lateral margins of the head slightly raised 

 and not rounded, under surface of head not channeled ; occiput slightly 

 emarginate ; prothorax but little narrower than the head, with a short, 

 rounded, spiuose protuberance on each side ; truncate in front and 

 somewhat flattened above ; mesothorax slightly narrowed aud a depres- 

 sion between it and the metathorax ; metathorax truncate and two- 

 spined, the whole thorax rogose and sub-spinose above; first much 

 smallest, sub-conical, with a rudimentary spine; abdomen round-ovate; 

 legs not slender. 



Dwells in the ground on hills near Aquia in Virginia. Slow in its 

 movements. 



