1988] 
Wheeler & Wheeler — Ants of Montana 
111 
Species-group s an guinea of formica 
Formica curiosa Creighton, flathead co. McGregor Lake 
(Creighton 1935. Type locality) (LA), roosevelt co. Culbertson 
(LA). 
Formica obtusopilosa Emery. Broadwater co. *5 mi E Town- 
send. 
Formica puberula Emery. Fergus co. *Rock Cr. 5800 ft in Big 
Snowy Mts. (slave: F. fusca). gallatin co. *Quake Lake 7000 ft 
(slave: F. lasioides). hill co. 16-30N-16E 3300 ft in Bearpaw Mts. 
Formica rubicunda Emery, hill co. 28-29N-16E 4000 ft in Bear- 
paw Mts. (BA). 
Formica subnuda Emery, cascade co. Belt (LA), chouteau co. 
17-28N-15E 3900 ft in Bearpaw Mts. (BA). Fergus co. *Maiden 
5000 ft in Judith Mts. glacier co. *13 mi SE St. Mary on US Hwy. 
89. glacier nat. pk. Avalanche Cr. (LA); Fish Cr. Ranger Sta. 
(LA), hill co. 16-30N-16E 3300 ft, 28-29N-16E 4000 ft, 19-28N-16E 
5000 ft, 23-28N-16E 4700 ft and 32-27N-16E 4700 ft in Bearpaw 
Mts. (BA). 
Polyergus breviceps Emery, carter co. *5 mi S Ekalaka (slave: 
Formica subsericed). Jefferson co. Elkhorn Mts. (M. R. Smith 
1947). lake co. Flathead Lake (M. R. Smith 1947). 
Interesting Montana Ants 
thatching ants. Figure 2. Thatching ant mounds are conspic- 
uous features of the grasslands. This is partly due to the size of the 
mound itself, but also to the fact that vegetation around the nest is 
taller than that of the surrounding prairie. Most of the nest is 
underground, but it is surmounted by a dome-shaped thatch 
mound. A typical mound is about 25 inches (66 cm) in diameter and 
12 inches (30 cm) high. It is constructed of twigs, grass blades, dried 
herbaceous stems or any other slender bits of material, assembled by 
the workers from neighboring vegetation. The thatching ants col- 
lected in Montana are Formica haemorrhoidalis, F. obscuripes, F. 
obscuriventris and F. oreas. 
mound-builders. The most common mound-builder is the har- 
vester Pogonomyrmex occidentals, which is distributed throughout 
