286 The Ohio Journal of Science [Vol. XIX, No. 5, 



McCook has made a thorough study. The nests are conical 

 mound from two to ten feet in convex diameter, consisting 

 principally of earth. They are located in open places in the 

 woods. 



The workers are very ferocious and will attack anyone 

 trespassing on their domains. They kill other ants by decapita- 

 tion. 



This species is a temporary parasite of F. fusca var. siihsericea. 



Rufa Group. 



1. Flexor of tibiae with erect hairs 2. 



Flexor surface of tibias without erect hairs 3. 



2. Thorax of large workers bright red like the head or at the most very feebly 



infuscated rufa aggerans Wheeler. 



Thorax of small workers deeply infuscated. Pubescence on the gaster weaker. 

 rufa aggerans var. melanotica Whir. 



3. Head and thorax of small workers spotted with brown. Frontal area shining, 



rufa obscuripes Forel. 



Head and thorax of small workers generally without brown spots; when 



spotted, the spots are pale. Frontal area slightly shining 



truncicola integroides Emery. 



F. rufa aggerans Wheeler. 



This robust species is the common thatching ant of the 

 Western States. Their nests are small, more or less flattened 

 mounds covered with coarse straws, sticks or vegetable matter. 



The Junior writer has observed this species attending 

 Piibilia concava on Helianthus sp.? and Thelia bimaculata on 

 locust. 



F. rufa aggerans var. melanotica Wheeler. 



This variety possesses the same nesting habits as the species 

 just mentioned except that their nests are smaller, being from 

 a foot to a foot and a half in diameter and are constructed in 

 grassy fields. 



The Senior author has observed this species having its 

 nest covered with the larvas of Coscinoptera doniinicana Fabr. 



F. rufa obscuripes Forel. 



Wheeler states that this form is imperfectly known. The 

 absence of erect hairs on the tibise of the legs is not a very strong 

 character for separating this species from other members of the 

 group. 



Nests of this ant are similar to those of F. aggerans. 



The species is peculiar to the Northwestern States, occurring 

 at elevations between 5,000-8,000 feet. 



