242 C. T. BRUES, 
During the past three winters which the writer has spent at the 
University of Texas, in Austin, Texas, he has seen stylopized spec- 
imens of three different species of Polistes, viz: P. rubiginosus ST. FARG., 
P. annularis Lınn., and P. texanus Cress. Both sexes of a species 
of Xenos were bred from specimens of P. rubiginosus, but only males, 
which represent a different species, were obtained from P. annularis ?). 
This preponderance of males is probably due to the season of the 
year, as the stylopized specimens of P. annularis were collected in 
the spring and the P. rubiginosus in the fall. Only one infested 
pecimen of P. texanus was seen and it contained only one pupa case 
from which a male had already emerged. 
The nest containing the specimens of P. annularis from which 
the specimens of Xenos pallidus were obtained, was collected along 
the banks of one of the creeks a few miles from Austin, attached to 
the overhanging side of a high cliff that afforded shelter for a large 
colony of such nests. As soon as it was apparent that the wasps 
were stylopized, a raid was made upon the remainder of the colony 
and several more nests secured after considerable difficulty, as the 
wasps had chosen rather inaccessible locations and are very savage 
toward intruders. To our surprise not a single specimen from these 
latter nests was infested, although the four specimens raised from the 
first nest each harbored from five to eight male Xenos, and one large 
larva which was dissected contained no less than 31 parasitic larvae 
of both sexes in various stages of development. From this it would 
seem that the wasps do not become infected simply from close 
proximity to a nest containing the parasites. Although the infected 
Polistes are not so active as normal individuals, they are nevertheless 
often seen feeding upon flowers and it would be easy for the young 
triungulins to become widely distributed among adjacent nests through 
the medium of flowers visited in common by members of various 
nests. The triungulins seem however, at least when an infected 
female Polistes is confined in a bottle, to cling tenaciously to her body, 
most probably until they are brought near the larvae of the wasps. 
If such be the case we can better understand the rather erratic 
1) These two species of Polistes are of about the same size and 
I am rather doubtful whether they represent more than varieties of a 
single species. They are usually quite different in coloration, but in a 
large series from this locality, it is difficult to draw a hard and fast 
line between the two forms. P. texanus is a somewhat smaller and 
quite different species. 
