A STUDY IN HYPERPARASITISM 25 
this puncture, for the eggs were always found fastened to the Apan- 
teles larva by the end of the long flexible stalk with which they are 
provided and the point of attachment was invariably a puncture hole. 
The egg hatches after 3 or 4 days, and the parasitic larva passes 
through five larval stages, the feeding period covering 10 to 15 days. 
From 3 to 4 weeks are passed as quiescent mature larva and as pupa, 
in the case of those individuals that will produce adults the same 
season, thus making the total period spent in the cocoon about 40 
to 50 days. Usually, however, there is but a single generation 
annually, 11 months or more being spent in the host cocoon. Like 
bifasciatus, this species hibernates asa maturelarva. The two species 
of Anastatus are the last of the hyperparasites attacking Apan- 
teles melanoscelus to appear in the spring, emerging about the middle 
of July. , 
Anastatus pearsalli is another of the comparatively small number 
of parasitic Hymenoptera that always produce females in parthen- 
ogenesis. In this respect it differs from the preceding species, which 
is arrhenotokous. 
ENCYRTIDAE 
SCHEDIUS KUVANAE HOWARD 
Schedius kuvanae, imported from Japan and established in the 
New England States as an aid in the control of the gipsy moth, is 
another egg parasite which has been reared in small numbers from 
cocoons of Apanteles melanoscelus. Its value as a primary parasite 
of the eggs of the gipsy moth is not materially lessened by its behavior 
as a hyperparasite, for the number of Apanteles destroyed is relatively 
so small as to be almost negligible. This hyperparasitism by Schedius 
is doubtless purely accidental. It is interesting, nevertheless, because 
it shows the adaptability of the larva to the conditions in which it 
finds itself, and further emphasizes the fact that parasitic Hymenop- 
tera are rarely absolutely restricted to one or another particular host. 
Specimens emerging from either eggs of the gipsy moth or from 
field-collected cocoons of A. melanoscelus attacked Apanteles cocoons 
readily in the laboratory. But they often experienced difficulty in 
piercing the tough cocoon, and exhibited a distinct preference for 
gipsy-moth eggs. When parasitic upon Apanteles the species is 
gregarious, from 6 to 17 individuals maturing in a single cocoon; and 
about 30 days are required for development from egg to adult. Sev- 
eral generations a year upon Apanteles are possible. The details of 
the life history of this species as an egg parasite have been published 
by Crossman (4) and need not be discussed here. In the case of co- 
ccons parasitized in the laboratory, the adults were sometimes unable 
to cut an exit opening and died without emerging. This indicates 
the unsuitability of Apanteles as a host for Schedius. 
PTEROMALIDAE 
DIBRACHYS BOUCHEANUS (RATZEBURG) 
(Fig. 8) 
This cosmopolitan species attacks a great variety of primary para- 
sites and very rarely itself acts as a primary parasite. At the gipsy- 
moth laboratory it has been reared in enormous numbers from Apan- 
teles melanoscelus, from numerous other species of Apanteles, from 
