1906.] Wheeler, The Ants of the Grand Canon. 34 ^ 



11. Pogonomyrmex barbatus rugosus Emery. — Many workers of 

 what I regard as a variety of this subspecies, were taken on the Angel 

 Plateau (3700 feet) and down to an altitude of about 3000 feet, but 

 not lower. The workers are somewhat smaller and smoother than 

 the typical rugosus, which is common in the deserts about Tucson. 

 The rugffi of the petiolar node are irregular and subreticulate. The 

 base of the gaster has two large yellow or red spots. The nests, which, 

 like those of the typical rugosus, are flat gravel discs 3 to 4 feet in 

 diameter, were especially abundant in the Coleogyne zone. The ants 

 were busily collecting the seeds of grasses and other herbaceous plants. 



12. Pogonomyrmex calif omicus Buckley. — This ant occurs from 

 just below the Angel Plateau to the river bottom, slightly over- 

 lapping the range of the preceding species. Its true home is in the 

 torrid deserts of southwestern Arizona and southern California, where 

 it prefers to nest in pure sand, I have also found it abundant at 

 Albuquerque, New Mexico, and in a somewhat depauperate condition 

 near Marfa in western Texas. Its nests are low, flat craters from 6 

 inches to a foot or more in diameter, with elegantly rounded slopes 

 and slanting, usually somewhat excentric entrances. The workers 

 can sting severely and those of large colonies actively resent any 

 interference with their nests. They run rapidly with the gaster 

 conspicuously elevated. 



13. Stenamma (Aphaenogaster) fulvum Roger var, texanuiu 

 Emery.— Five workers taken under stones at the Indian Garden agree 

 with specimens of this variety from Austin and New Braunfels, Texas, 

 except that they are somewhat larger and have the head and thorax 

 somewhat more coarsely sculptured. The body is slightly redder 

 and the gaster is infuscated. In Texas the variety occurs in rather 

 shady damp portions of the live-oak woods and mesquite thickets, 

 and is never found in dry, open country. 



14. Leptothorax nitens Emery. — A few colonies of a pure yel- 

 low form of this species were seen under stones in the Kohonino 

 Forest on the rim of the canon. 



15. Leptothorax neomexicanus Wheeler. — ^A single small colony 

 of this species was found under a stone in the same locality as the 

 preceding. 



Subfamily Dolichoderin^. 



16. Liometopum apiculatum luctuosum Wheeler. — This sub- 

 species is common in the Kohonino Forest on the rim of the caiion and 

 extends down the walls sparingly to an altitude of about 4000 feet. 



