wheeler: ants of the genus formica. 447 



Pilosity and pubescence yellowish, abundant, the former suberect, 

 absent on the upper surface of the gaster, which is covered with rather 

 long, appressed pubescence. Legs covered with short, suberect 

 hairs. Eyes hairy. 



Head and thorax, including the frontal area, opaque; gaster some- 

 what shining. 



Black; legs and genitalia yellow, coxae and bases of the femora 

 dark brown. Wings infuscated as in the female. 



Host (Temporary). F.fusca var. subsericea. 



Type locality. — Connecticut: (Mayr). 



Massachusetts: Stony Brook Reservation, Blue Hills, near Boston, 

 Ellis ville (Wheeler); Wellesley (A. P. Morse). 



Maine: Sebascodegan Island, Casco Bay (Wheeler). 



New York: Saugerties (G. v. Krochow); Ithaca (Cornell Univ. 

 Coll.). 



New Jersey (Mayr). 



District of Columbia: Washington (A. Forel). 



Virginia (Mayr). 



Indiana: Culver, Tippecanoe Lake (W. S. Blatchley). 



Illinois: Rockford (Wheeler). 



Wisconsin : White Fish Bay, near Milwaukee (Wheeler) . 



Colorado: Florissant (Wheeler); Flagstaff Mt., Boulder (T. D. 

 A. Cockerell). 



British Columbia: Carbonate, Ravelstoke (J. C. Bradley); Golden 

 (W. Wenman). 



Ontario: Toronto (R. J. Crew). 



This ant was originally described from Connecticut, but in a later 

 paper (1886) Mayr cited it from several of the Atlantic States and also 

 from Colorado, California, New Mexico, and Arizona. As it is very 

 rare in Colorado, and as I have never received it from other Western 

 States, I believe Mayr must have confounded it with specimens of 

 F. rufa aggerans. This would be easy for large greasy specimens of 

 aggerans are very similar to large workers of obscuriventris. In 

 fresh specimens, however, the gaster of the latter has a very different 

 appearance, being much as in mclanotica, but it is readily distinguished 

 from this form by the uniform deep red color of the head, thorax, 

 petiole, and legs. 



F. obscuriventris nests under large stones in open woods, often 

 banking the edges of the stones with vegetable debris. The colonies 

 are much smaller than those of Integra, and inicgroidcs and rarely 

 extend over more than one nest. Many queens are retained in the 



