286 
PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
her to select certain hosts in preference to certain others, as in the 
-instance of the American and European races of Parexorista chelonise. 
Again, it may be in the ability of the young larvae to complete their 
development upon a certain host, as in the case of Tachina mella and 
TacMna larvarum. Or again, it may be that the difference lies as be- 
tween Apanteles lacteicolor Vier. and A. conspersse Fiske in the methods 
of attacking the host. 
As has already been recounted, no less than 45,000 adults of 
Apanteles lacteicolor Vier. have been reared at the laboratory and lib- 
erated in the field. In addition a very large number has been reared 
under close observation during the winter or spring, and there has 
been a large number of more or less successful reproduction experi- 
ments conducted, in most instances with great care. In all this time 
there has not been a single exception to the rule, that the larva of 
Apanteles lacteicolor Vier. is solitary, and kills its host before issuing 
from its body. Nothing whatever, either in the field, or in the many 
experiments in reproduction, or in the occurrence of the parasite in 
shipments of larger caterpillars from Europe, has indicated in any 
way that it may ever attack the large caterpillars successfully, or 
that it is ever anything else than solitary. 
Had Apanteles conspersse Fiske been received as a parasite of the 
Japanese brown-tail moth without other data than the mere rearing 
record it would undoubtedly have been considered as identical with 
Apanteles lacteicolor Vier., but it is impossible so to consider it in view 
of the fact that it is not solitary but gregarious; that it attacks, not 
the small but the large caterpillars, and, if appearances of the material 
from Mr. Kuwana were not deceiving, that the host is left alive instead 
of being killed before the emergence of the parasite larva. These 
differences are, or ought to be, sufficient to make of it another species. 
It is not at all improbable that if it were given the opportunity it 
would attack the caterpillars of the European brown-tail moth, and it is 
hoped that enough can be collected in Japan and forwarded to Amer- 
ica to make the experiment possible. 
METEORUS VERSICOLOR WESM. 
A very few specimens of this parasite were imported in 1906 with 
caterpillars of the brown-tail moth and the gipsy moth from several 
European localities. In 1907, as already stated in the account of 
Apanteles lacteicolor Vier., a few specimens of Meteorus (fig. 68) were 
reared from caterpillars imported in hibernating nests the winter be- 
fore;. There were very few, less than 100 all told, and not enough to 
colonize with any likelihood of success. It was therefore decided to 
use them in a series of reproduction experiments, on the chance that 
a much Larger number might be reared for colonization. 
