264 



PARASITES OF GTPSY AND BROWN-TATL 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- 



FiG. 62. — Meteorus versicolor: Immature larva from hibernating caterpillar of the 

 brown-tail moth. Much enlarged. (Original.) 



istic of its hibernating condition. These larvas 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, Marchal, 

 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 type. 



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. Q3.—Zygobothria ni- 

 dicola: First-stage larvae 

 in situ in walls of crop of 

 hibernating brown-tail 

 moth caterpillar. Great- 

 ly enlarged. (Original.) 





