514 WHEELER. 



postpetiole is distinctly though feebly shining owing to the more 

 superficial punctuation. The rugae on the head and thorax are much 

 more distinct, coarser and further apart. The blunt, erect hairs on 

 the upper surface of the body, especially on the head, thorax and 

 pedicel are much longer, coarser and glistening white. The hairs on 

 the legs seem also to be somewhat coarser than in the various forms of 

 canadensis. The spines of the epinotum are scarcely more than half 

 as long as their distance apart at the base, acute and rather slender. 

 The antennal scapes reach about half way between the eyes and the 

 posterior corners of the head and the basal funicular joints are dis- 

 tinctly shorter and more transverse than in canadensis and its varie- 

 ties. Color dark brown or castaneous, head and sometimes the gaster 

 darker and more blackish; mandibles, antennae and legs pale brown; 

 middle portions of femora, but not the antennal clubs, infuscated. 



Female. Length: 3.5 mm. 



Very similar to the worker, the rugosity of the head and thoracic 

 dorsum and the pilosity of the head and thorax even a little coarser 

 and more conspicuous. Body uniformly castaneous, except the pale 

 incisures of the gaster. Wings grayish hyaline, veins pale brown, 

 pterostigma dark brown. 



Male. Length 3-3.5 mm. 



Much smaller than the male of canadensis and acervorum. Dark 

 brown; head black, mandibles and legs pale brown, tarsi paler. 

 Wings white, with pale brown veins and stigma. Sculpture of head 

 and thoracic dorsum distinctly more superficial than in canadensis 

 var. yankee and caldcroni, the head, especially, more shining. Pilos- 

 it}^ not more abundant, but paler. 



Described from numerous specimens of all three phases taken from 

 small colonies under stones in several localities (Manitou, Cheyenne 

 Creek, Red Rock Canyon, Williams Canyon) near Colorado Springs 

 during July and August, 1903. This form is so distinct that it might 

 be regarded as an independent species, but as it has the shape of acer- 

 vorum and the median impression of the clypeus I prefer for the present 

 to regard it as a subspecies. 



52. Leytothorax {Mychothora.x) emersoni Wheeler subsp. glacialis 

 Wheeler. 



Colorado: Florissant 8500 ft. (Wheeler). 



As I have shown (Bull. Wis. Nat. Hist. Soc. 5, 1907, p. 78 et seq.), 

 this subspecies lives in the colonies of Mynnica brevinodis var. sub- 

 alpina in much the same manner as the typical emersoni of New Eng- 

 land and Canada lives with M. brevinodis var. canadensis. 



