No. 415.] NESTS OF AMERICAN ANTS. 531 
as both are of considerable interest in connection with our 
closely allied American species, Solenopsis molesta : 
“The Solenopsis may establish itself near almost any other 
ants of our country. It is found especially with Formica 
fusca, F. rufibarbis, Polyergus rufescens, F. rufa, F. pratensis, 
F. sanguinea, F. cinerea, Tetramorium cespitum, and Myrmica 
scabrinodis. Frequently it is possible to observe that the two 
nests are in close contact with each other. The Solenopsis 
nest may partially surround that of its neighbors, or it may 
even be excavated in part in the masses of the earth separating 
the galleries of the latter. That the two nests so near each 
other are not merely two contiguous nests, but deserve a 
special name such as the term ‘double nest’ employed by 
Forel, is proved by the fact that fine connecting galleries 
enable the Solenopsis to make incursions into the nests of 
their neighbors, where, as we shall see, they find an abundance 
of food. Wasmann (91, p. 21) mentions an extremely populous 
nest provided with some twenty queens and extending in a 
semicircle around the subterranean portion of a Formica pra- 
tensis nest, with which it communicated by means of fine pil- 
laging galleries. Forel and Wasmann, however, have also met 
with isolated nests. At Beauvais I was able to ascertain, by 
following carefully during several hours the spading of a piece 
of land which was exposed to the south and had been left 
untouched for several years and was almost devoid of stones, 
that the nests of Solenopsis may often be isolated, or at least 
noticeably distant from the nests of any other species. Never- 
theless, this distance does not at all exclude the possibility of a 
communication by means of long galleries with the ant nests of 
the neighborhood, €.g., with those of the Tetramorium, which 
were not rare in the same piece of ground. It is probable that 
the Solenopsis, when necessary, manages to go a considerable 
distance in search of the ant pupee that appear to constitute its 
Principal food, but there is, nevertheless, a propensity to settle 
near the nests which furnish this food, and this approach is 
favored by the presence of stones, under which ants have such 
à pronounced tendency to shelter themselves. . .. In the sandy 
! Emery (95) also records the occurrence of such nests near Bologna, Italy. 
