562 bulletin: museum of comparative zoology. 



142. F. microgyna rasilis var. pullula, var. nov. 



Worker. Length 3.5-6 mm. 



Differing from the typical rasilis in color, the red portions of the 

 body being decidedly darker and more brownish red. The petiole 

 is more compressed anteroposteriorly, with a sharper border, which is 

 more produced upward in the form of a blunt point. The erect, 

 blunt hairs on the upper surface of the head and thorax, especially 

 on the latter, are shorter and even less numerous. In many specimens 

 they are altogether lacking on the front and thorax. 



Female. Length 5 mm. 



Differing from the female of rasilis in color and in the shape of the 

 petiole. Head, thorax, and gaster dark brown or blackish; mandibles, 

 clypeus, cheeks, and gula dark red ; antennal scapes, propleurae, epi- 

 notum, petiole, and legs somewhat paler, dull red. Head and thorax 

 opaque, gaster slightly glossy, with very short, rather sparse pubes- 

 cence. Wings grayish hyaline; stigma light brown, veins paler. 

 Petiole as in the worker, but its border even more produced and atten- 

 uated in the middle. 



Described from numerous workers and three winged females taken 

 from two colonies at Flathead Lake, Montana, by Prof. C. C. Adams. 

 In the coloration of the worker and shape of the petiole tliis variety 

 resembles F. adamsi Wheeler, but is larger and the head and thorax 

 are at most very faintly and diffusely clouded with fuscous and not 

 spotted. 



143. Formica microgyna rasilis var. nahua, var. nov. 



Worker. Length 4-6 mm. 



Differing from the worker of the typical rasilis in having the petiole 

 narrower and its margin distinctly blunter, the erect, obtuse hairs on 

 the head and thorax somewhat more numerous and also present on 

 the border of the petiole and on the gula; the sculpture is somewhat 

 sharper, so that the sides of the head are opaque like the remaining 

 surface, and the color of the gaster is darker and more blackish. 

 Even the largest workers have no infuscation on the ocellar triangle 

 and very rarely have faint blotches on the pro- and mesonotum. 

 The tibiae are naked as in the typical rasilis. 



Female. Length 6 mm. 



Differing from the female of rasilis in being a little larger and more 

 robust, in having more numerous erect, obtuse hairs on the head, 

 thorax, and gaster, a blunter petiolar border and in color, which is 



