226 
Psyche 
[December 
30. Formica rufa obscuripes Forel 
This ant is a very common occupant of the Snake River 
Plains, where, as populous colonies, it inhabits large 
thatched mounds, usually surrounding plants of sagebrush. 
It has been taken by the writer as far north as Stanley, 
where it is replaced by the variety melanotica Emery. 
Winged sexes appear during late June near Twin Falls. 
31. F. subpolita Mayr. 
Common to the semidesert plains and occurring through- 
out the state, this species is found inhabiting nests beneath 
rocks, and less commonly small crater mounds. Winged 
forms appear in early July at Twin Falls. Coccids and pseu- 
doscorpions have been removed from nest chambers. 
32. F. subpolita camponoticeps Whir. 
This variety is of less common occurrence than is the typ- 
ical species but, nevertheless, very often nests beneath rocks 
under similar conditions and in the same localities as the 
typical subpolita. Workers were infested with the fungus 
Laboulbenia formicarum Thaxter. 
33. F. fusca neorufibarbis Emery 
F. neorufibarbis lives beneath rocks or in earthen mounds 
in rather moist, shady and grassy areas throughout the 
Snake River plains. It feeds chiefly on honeydew and 
dead insects. 
34. F. fusca subsericea Say 
This very common ant is found in practically all parts of 
the region where it inhabits nests beneath rocks or occupies 
large earthen mounds. 
35. F. fusca subaenescens Emery 
F. subaenescens is more rare than is subsericea and occu- 
pies more moist habitats. Where found, the nests are be- 
neath large rocks. The an thas been collected near Twin 
Falls and Stanley. 
36. F. neogagates Emery 
A few nests of this species have been found by the writer 
