MOUNTAIN ANTS OF NORTH AMERICA. 503 



15. Myrmica hrevinodis var. decedens Wheeler. 



Colorado: Buena Vista, 7900 ft. (type locality) and Florissant, 

 8500 ft. (Wheeler). 



New Mexico: Pecos Mts.; San Miguel County (Mitchell). 



The workers from New Mexico are considerably darker than the 

 types and may prove to belong to a distinct variety. 



16. Myrmica hrevinodis var. alashensis var. no v. 

 Worker. Length 3.5 mm. 



Resembling the variety sidcinodoides but smaller and of a different 

 color. Head black above; thorax, pedicel and gaster castaneous; 

 mandibles, antennae and legs brownish yellow. Antennae slightly 

 thicker at the base than in sulcinodoides. Rugae on the clypeus very 

 coarse, much fewer in number (only 8) than in other forms of the 

 species; frontal area distinctly outlined, subopaque and very finely 

 punctate, not longitudinally rugulose. Rugae on the sides of the 

 head coarsely reticulate, not longitudinal, those on the thorax and 

 pedicel much as in sulcinodoides but a little finer; surface of head, 

 thorax and pedicel a little more opaque. Epinotal spines somewhat 

 shorter than the base of the epinotum, curved downward at their tips. 

 Summit of petiolar node distinctly- more rounded than in sulcinodoides 

 and transversely rugose, postpetiolar node less convex behind. Pilos- 

 ity like that of sulcinodoides. 



Described from eight workers taken at Seward, Alaska by Mr. F. H. 

 Whitney. 



17. Myrmica hrevinodis var. subalpina Wheeler. 



British Columbia: Hector, Field and Carbonate (J. C. Bradley); 

 Emerald Lake (Wheeler). 



Alberta: BanfP (Wheeler); Jasper (C. G. Hewitt). 



Washington: Orcus Island (W. M. Mann). 



This variety, originally described from Florissant, Colo., forms 

 flourishing colonies under logs and stones in moist, sunny places. 

 I found it very abundant on the southern slope of Tunnel Mt. at BanfP. 

 It closely resembles the eastern var. canadensis Wheeler, but the wings 

 of the male and female are whitish hyaline throughout and not infus- 

 cated at the base. The workers of certain colonies present transitions 

 in color to the var. sulcinodoides, but this forms smaller colonies and 

 prefers higher elevations. 



18. Myrmica mexicana Wheeler. 



This species, related to our eastern M. punctiventris Roger, was taken 

 by Dr. Mann at Guerrero Mill, Hidalgo, Mexico. 



