PARASITES OF GIPSY-MOTH CATERPILLARS. ZO} 
Two lots of each generation were collected after the healthy parasites had issued, 
and the results follow: 
First generation. | Second generation. 
Cocoons. | Per cent. | Cocoons. | Per cent. 
MCAS ATLL CLS mers ere eee eee ee ee eee es ee we aD 543 66.5 636 26 
LED Del g en ite ered os a Oe ee Oe ae eee en ree a 162 20 1, 207 50 
She Ce ORS or ene re pee erty ee el EE Ee ko et Ze, 2.5 102 4 
NRE eer Geert tee ene eee: ney FTP ANA re NE el eee oo 89 11 1469 120 
MCCS MY aN, Ne ere eer NS Sas at hoe meng Soin 2 816 100 2,414 100 
1 Oct. 20. 
Other collections of cocoons from colonies where the Apanteles was liberated too 
late in the season to permit of two generations showed a high rate of hyperparasitism 
in the single generation, actually the first but corresponding to the second. Com- 
parison in this instance is valueless, as local conditions enter in which can not be 
gauged. 
This rather lengthy summary of a study in hyperparasitism has 
been prepared and is here presented with the object of illustrating 
the somewhat modified stand which it has been necessary to take 
concerning the subject in its relation to the project of parasite intro- 
duction. Were it within the bounds of possibility to introduce into 
America the parasites of the gipsy moth (Apanteles fulvipes, for 
example) without introducing the secondary parasites which preyed 
upon them abroad, it would unquestionably be possible to secure a 
greater meed of efficiency in America than that which the same para- 
sites were capable of attaining in their native countries. This is on 
the supposition that the parasites themselves are no more likely to be 
attacked by the American hyperparasites than their hosts are likely 
to be attacked by the American primary parasites. 
That the assumptions are fallacious, to a certain extent, is well 
proved by the results following the temporary establishment here of 
Apanteles fulvipes, as recounted above, and that the same results 
as those which followed the exposure of this parasite to American 
hyperparasites will result in the instance of others among the im- 
ported parasites is more than likely. In the case of Compsilura 
concinnata and Apanteles lacteicolor Vier. it is proved. 
The truth of the matter is that the secondary parasites are very 
far from being as closely restricted to one or two species of hosts as 
are the primary parasites. This is in part due to the fact that they 
represent for the most part a much more degraded form of para- 
sitism. Species like Dibrachys boucheanus, which is perhaps as 
generally abundant and omnivorous as any of the parasitic Hymen- 
optera, will attack anything which is dipterous or hymenopterous, 
provided it is physically suitable as food for its larve. Apanteles 
fulvipes and caterpillar parasites generally are governed in their host 
