PARASITISM OF BROWN-TAIL MOTH IN AMERICA. 145 
CHALCIS sp. 
Upon several occasions specimens of Chalcis have issued from 
cocoons of the brown-tail moth collected in the open. The species 
has not been definitely determined nor compared with Chalcis ovata, 
because it is thought likely at the present time that two species may 
be confused under that name. One of them is believed to be a pri- 
mary parasite of lepidopterous pup and the other to be essentially 
a secondary parasite attacking tachinid puparia. 
EUPHOROCERA CLARIPENNIS MAca. 
. 
Several times reared from brown-tail caterpillars collected in the 
field, but always, apparently, rare in this connection. 
TACHINA MELLA WALK. 
Never a common parasite in connection with this host. Usually 
about on a par with Euphorocera and without economic significance. 
PHOROCERA SAUNDERSII WILL. 
A single specimen thus determined by Mr. Thompson was reared 
in 1910 under circumstances which quite conclusively indicate this 
host relationship. 
EXORISTA BOARMLE® Coa. 
Like the above, only a single individual of this species has been 
reared from brown-tail caterpillar collections, but under circumstances 
which were not so decisive as in the last-mentioned instance. Mr. 
Thompson is authority for this determination also. 
UNDETERMINED TACHINID: ‘‘ NATIVE PARASITE OF CHRYSORRH@A.’’ 
One of the most remarkable instances of attack on an unsuitable 
host by a tachinid parasite is that of the species which in the labora- 
tory notes is always referred to as above, upon the caterpillars of the 
brown-tail moth. The history of this species, the identity of which 
is very much in doubt, is in certain respects comparable to that of 
Tachina mella in its relations to the gipsy moth. As may be seen by 
the summarized results of the rearing work in 1910 (Table VI), it 
is not infrequently a parasite of some little consequence, and in all 
many hundreds of its larvee have been secured from field collections 
of brown-tail caterpillars. 
Invariably, however, these larve died without forming perfect 
puparia. For a long time it was thought that this was due to unfa- 
vorable surroundings at the time when pupation was attempted and 
95677 °—Bull. 91—11——_10 
