No. 415.] NESTS OF AMERICAN ANTS. 533 
species of ants are unable to enter the nests of their neighbors, 
as the galleries of the latter are too narrow ; and when the 
two species happen to meet one is inclined to believe, with 
Forel (74, p. 246), that the small size of the Solenopsis renders 
them invisible to the larger ants. Then, too, in case of a con- 
flict, the Solenopsis are numerous enough and sufficiently well 
armed with stings to kill even Formica sanguinea. In my 
double artificial nests I often saw one of the latter killed by a 
group of five or six Solenopsis, but on such occasions I also 
found a considerable number of Solenopsis cadavers on the 
refuse-heaps.” 
II. Solenopsis molesta Say. 
The European S. fugax is represented in North America by 
a very closely allied species, — S. molesta Say. (= S. debilis 
Mayr.) — a minute yellow ant with yellow queens and dark 
brown males. The species has a very wide geographical range. 
It has long been known from the Eastern and Northern States 
and appears to be equally common in Texas. Although not 
mentioned in Forel's monograph (99) it extends through 
Mexico, where I have taken it as far south as Cuernavaca in 
Morelos. Emery has described a variety validiuscula from 
California. 
The habits of S. molesta, so far as I have been able to 
observe them, are the same as those of S. fugax. Although 
like its European congener it sometimes occurs in isolated nests, 
and even in houses, it has, nevertheless, a decided predilection 
for forming compound nests, essentially like those of S. fugax, 
with larger ants. In the Northern States it often consorts 
with the different species of Formica, Lasius, Stenamma, 
and Myrmica. In Texas it is of almost regular occurrence in 
the large nests of Pachycondyla harpax and Odontomachus 
clarus, and often occurs with the different earth-inhabiting 
Species of Camponotus (C. fumidus, var. festinatus Buckley ; 
C. maculatus, subsp. sansabeanus). In Mexico I have taken it 
with a variety of Odontomachus clarus. In one nest of S. molesta, 
discovered near Austin, I found the workers feeding on a dead 
cricket lying in the galleries of Pachycondyla harpax. As 
