1917] Wheeler—Social Parasitism of Lasius subumbratus Viereck 169 
of them is parasitic on some one of our varieties of L. niger. I 
have repeatedly found deilated queens of aphidicola in small 
cavities under stones as if in the act of founding colonies inde- 
pendently in the same manner as most ants, but never with brood. 
Nor have I ever been able to find a mixed colony of L. niger var. 
americanus and aphidicola, even in Illinois where both forms are 
common in the same localities. The only indication that any 
American form of wmbratus may be a social parasite is furnished 
by some specimens of subumbratus collected by Mr. W. Reiff in 
Nova Scotia and some experiments by Tanquary on minutus. At 
Bedford, near Halifax, Mr. Reiff took six deilated swbhumbratus 
queens from three colonies of what I recorded at the time (1910) 
as “the large yellowish form of Lasius niger var. neoniger Emery.” 
Since the discovery of Pergande’s types of Alaskan ants I can now 
state definitely that this variety is sitkaésis. As Reiff’s speci- 
mens were not accompanied by notes, the parasitism of swbum- 
bratus could only be conjectured. Tanquary introduced succes- 
sively some eighty-eight of the small, active queens of minutus into 
twenty different colonies of LZ. americanus, nearcticus, brevicornis, 
claviger and interjectus and obtained one case of adoption. This 
was in a colony of eight workers and a large number of cocoons of 
americanus. He concludes that “although one adoption out of 88 
attempts is a small percentage, yet I think the ease with which this 
queen was adopted is very suggestive, and taken together with the 
facts mentioned above, namely the sporadic occurrence of the 
species, the very large number of females produced, the small 
size of the females, the fact that these females have not been seen 
in the act of founding a colony and one additional fact that may be 
mentioned, the mimetic coloration of the females (the color of 
these females is exactly the same as that of the darker form of 
americanus), I think justifies us in concluding that the queen of 
this species is in all probability, temporarily, parasitic upon the 
common L. americanus.” 
My observations at Cloudcroft leave no doubt concerning the 
parasitism of the subspecies subumbratus on two forms of L. niger, 
the var. sitkaénsis Pergande and the var. neoniger Emery. ‘The 
former, as I have recently shown (1917), is the common form of 
niger at higher altitudes and latitudes from Alaska to Maine and 
Nova Scotia and southward along the ranges of the Sierra Nevada 
