MOUNTAIN ANTS OF NORTH AMERICA. 509 



node is much less compressed anteroposteriorly, its posterior surface 

 being much more convex than in typical nevadensis. The color is 

 considerably darker, the body being castaneous, with the head and 

 gaster, except its incisures, blackish, the mandibles, clypeus, antennae 

 and legs yellowish brown, the femora infuscated in the middle. Pilos- 

 ity as in the typical form. 



Female (dealated). Length: 3.5 mm. 



Smaller than the female of typical nevadetisis, with longer and more 

 slender epinotal spines and the funicular joints 2-8 shorter. Sculp- 

 ture of the head, thorax and petiole a little coarser. Petiolar node like 

 that of the worker. In the typical form it is much compressed antero- 

 posteriorly and has a sharp, trans^-erse superior border. There is 

 very little difference in color between the two forms. 



Described from numerous workers and a single female taken from 

 small colonies nesting under the edges of stones in Tenaya Canyon, 

 Yosemite Valley, Cala. Seven workers from Angora Peak, 8600 ft., 

 near Lake Tahoe, Cala., though differing in certain details of sculp- 

 ture are nevertheless referable to this subspecies. 



39. LeptotJwrax rugatuhis Emery. 

 South Dakota: (Rergande). 



Colorado: (Pergande); Cheyenne Canyon, near Colorado Springs 

 (Wheeler) . 



Washington: Seattle (T. Kincaid). 



Montana: Helena (W. M. Mann). 



Studv of much more material of this form and its varieties than 

 I possessed when I wrote my " Revision of the North American Ants 

 of the Genus Leptothorax" (Proc. Acad. Nat. Sci. Phila., 1903, pp. 

 215-260) convinces me that rugatulus is really a distinct species, as 

 Emery maintained, and not a subspecies of curvispinosus Mayr. The 

 latter is the most generally distributed and abundant Leptothorax in 

 the Eastern and Central States as far west as Missouri, but rugatulus 

 and its varieties are confined to the Western States. The two forms 

 also differ in habits, rugatulus and its varieties nesting under stones 

 and curvispinosus in hollow twigs and old galls. 



40. Leptothorax rugatulus var. cockerelli Wheeler. 



New Mexico: Las Vegas Hot Springs, type locality (T. D. A. 

 (Jockerell). 



Arizona: Miller, Carr and Ramsay Canyons, Huachuca Mts. 

 (Biedermann, Mann and Wheeler). 



