No. 415.] NESTS OF AMERICAN ANTS. 539 
of the double nests of the Formica rufa and Formicoxenus 
could be formed even within one of these circumscribed vege- 
table growths. The guest ant could inhabit the central cap- 
sule (in which the gall fly passes its pupal stage), while the 
host ant might occupy the 
chambers dug in the ligneous 
substance of the gall. Iam 
led to this supposition by 
finding that a new species of 
Leptothorax, which regularly 
nests in the Holcaspis cinero- 
sus galls formed on the live pes eens Peeve wid: 
oaks about Austin, prefers giu es 
the small central capsule as a nursery. Here the single 
queen lives wedged in between the eggs, larvae, pupæ, and a 
few workers, while the chambers of the gall are commonly 
tenanted by the bulk of the workers. 
14. Leptothorax (Dichothorax) pergandei Emery (Fig. 14). 
Our knowledge of this species, too, is extremely meager. It 
was described by Emery (95, pp. 323, 324) from specimens 
taken as guests in a nest of Monomorium minutum, var. mini- 
mum, at Washington, D. C., by Mr. Pergande. 
I5. Leptothorax emersoni n.sp. 
The Leptothorax described in detail in the first part of this 
paper may be included among the guest ants, although it 
certainly resembles in many respects the cases of dulosis and 
Social parasitism. 
UNIVERSITY oF TEXAS, AUSTIN, TEXAS. 
(To be continued.) 
