264 
PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
similar from those of the first-stage Meteorus, and are so little differ- 
entiated as to be indescribable. 
The hibernating stage of Meteorus is in remarkable contrast to 
that of Apanteles. The accompanying drawing (fig. 62) is from a 
balsam mount, and represents an individual which has resumed activ- 
ity and grown very slightly larger and plumper than is character- 
FlG. 62. — Meteorus versicolor: Immature larva from hibernating caterpillar of the 
brown-tail moth. Much enlarged. (Original.) 
istic of its hibernating condition. These larvae are curiously anoma- 
lous, in that though they are actually first-stage, the head alone is 
considerably larger than the original egg as deposited by the mother. 
An interesting series of dissections made by Mr. 
Timberlake in the spring of 1910 served to ex- 
plain this apparent anomaly. The eggs are very 
small when first deposited and almost globular. 
Apparently with the beginning of embryological 
development they begin to grow and by the time 
the inclosed embryo begins to assume the charac- 
teristics of the larva they have reached a diame- 
ter at least four times greater than that of the 
newly deposited egg. The enormous chitinized 
head, with strong, curved mandibles, is in strange 
contrast to the undifferentiated cephalic segment 
of Apanteles and is apparently closely analogous 
to the large-headed, heavily mandibled larvae of 
the Platygasters, as described by Ganin, March al, 
and others. There are many points of resemblance 
between the two forms, and it would seem, without 
going into the matter at all deeply, as though the 
type of embryological and early larval development 
characteristic of Meteorus were essentially the same 
as that of the Platygasters and many ichneumonid 
genera, while that of Apanteles would have to be 
considered as of an essentially different tj T pe. 
In both Apanteles and Meteorus the later larval stages are much 
more conventionalized and more like the familiar type. 
The position assumed by the Apanteles larva is not very definitely 
known. The Meteorus larva usually lies superior to the alimentary 
Fig. Cfi.—Zygobothria vi- 
dicola: First-stage larvae 
in situ in walls of crop of 
hibernating brown-tail 
moth caterpillar. Great- 
ly enlarged. (Original.) 
