THE CHALCIDOID GENUS PEKILAMPUS. 45 



We know that the adult of one of the European species of Pen^ 



lampus hibernates in the puparium of certain tachinids parasitic on 



the gipsy moth and brown-tail moth. Most of these tachinids, like 



the summer-issuing hymenopterous parasites, pupate comparatively 



early in the fall, thus making the two cases similar. For this reason 



the writer feels justified in sm-mising that the same thing occurs in 



the case of Perilampus hyalinus parasitic on the summer-issuing 



Hymenoptera. 



As A Parasite of Other Hosts. 



There is another group of parasites of the fall webworm which 

 hibernate either as partially grown or as full-fed larvae within the 

 pupae of their host . These include certain large solitary ichneumonids, 

 Anomalon ambiguum Norton, Ichneumon cinditarsis Provancher, and 

 Melanichneumon sp. At least one species of Tachinidae has also been 

 found hibernating in this manner in Massachusetts. We have not 

 actually found Perilampus to be a parasite of any of the ichneumonids 

 named above, but only a very small number of the larvae of these 

 parasites have been seen.^ There seems to be no good reason why 

 the secondary should not attack these hibernating hymenopterous 

 larvae, and it is practically certain that the examination of a con- 

 siderable number would show the planidium to be present. 



We have absolute proof, however, that it does attack the hiber- 

 nating tachinids,^ having found the planidium actually within the 

 maggot of this species within the pupa of Hypliantria. Wliether or 

 not the adult Perilampus is able to make its way through the pupal 

 shell of the fall webworm (presuming that the tachinid completes its 

 larval development and pupates internally) we are unable to state 

 definitely, as no record has been made of Perilampus having issued 

 from these ]ni]^ae. There seems to be little doubt as to its ability 

 to do this, as it has very powerful jaws. Specimens in the laboratory 

 will eat away quite a large quantity of cork in attempting to escape 

 from a vial in which they have been confined. 



LATER LARVAL STAGES. 



On the return of warm weather in the spring, the winter having 

 been passed upon the various hosts in the manner indicated in the 

 preceding pages, the planidium begins feeding by sucking the juices 

 of its host. Growth takes place gradually and first becomes apparent 

 through the planidium taking on a banded appearance due to the 



1 It has since been found by Mr. H. E. Smith within the larvae of Ichneumon (which attaelvs the pupa 

 of the host) and that of Exochilum, which hibernate in what must be considered as an embryonic state 

 within the Hyphanlria pupse.— W. F. Fiske. 



2 Probably Compsilura concinnata, the recently imported parasite of the gipsy and brown-tail moths. 



19242°— 12 3 



