MOUNTAIN ANTS OF NORTH AMERICA. 515 



53. Leptothorax {M ychotkorax) emersoni subsp. hirtipilis suhsp. nov. 

 W^orker. Length 2.5 mm. 



Differing from the typical emersoni and the preceding subspecies in 

 the following characters: the mesoepinotal constriction is more pro- 

 nounced, the pro- and mesonotum being somewhat more con\'ex and at 

 a higher level than the base of the epinotum. The sculpture is much 

 coarser, the rugae on the head being very sharply defined even on the 

 occiput and posterior corners; on the thoracic dorsum the rugae are 

 vaguely longitudinal. The head, thorax and petiole are decidedly 

 opaque. The pilosity is much coarser and more abundant, especially on 

 the thorax and legs. The color is a little darker than that of emersoni 

 and glacialis, with only the anterior border of the gaster yellowish. 



A single specimen taken from a nest of Myrmiea brevinodis var. 

 snhaJpina on the southern slope of Tunnel Mt., at Banff, Alberta. 

 This shows that the habits are symbiotic as in the other forms of the 

 species. 



54. Leptothorax (Mychothorax) hirticornis Emery subsp. formidolo- 

 sus \Yheeler. 



Colorado: Flagstaff Mt., Boulder Co. (T. D. A. Cockerell). 

 South Dakota: Hill City (Pergande Coll. Nat. Mus.). 



55. Aphaenogaster suhterranea Latr. subsp. occidentalis Emery. 

 Washington: Pullman, type locality (Pergande); Pullman and 



Wawawai (W. M. Mann) ; Almota (A. L. Melander) ; Olympia (T. 

 Kincaid) . 



Oregon: Ashland (W. Taverner). 



California: Pacific Grove, Mt. Tamalpais, Yosemite and Lake 

 Tahoe (Wheeler) ; Palo Alto and King's River Canyon (H. Heath) ; 

 Corte Madera Creek, Santa Cruz Mts. (W. M. Mann); Mountain 

 View. 



Idaho: Moscow (J. M. Aldrich). 



Utah: East Mill Creek, Salt Lake Co. (R. V. Chamberlin). 



Colorado: Cheyenne Canyon near Colorado Springs and Boulder 

 (Wheeler). 



Montana: Helena (W. M. Mann). 



British Columbia: Dog Lake, Penticton (C. G. Hewitt). 



This subspecies is extremely common in both the Coast Range and 

 the Sierras of California from sea-level to an elevation of 6000 ft. It 

 appears to be equally common in Oregon and Washington but is 

 much more sporadic in the other localities cited. 



