20 BULLETIN 1363, U. S. DEPARTMENT OF AGRICULTURE 



ARCTIIDAE 



Differing but slightly from the lip ar ids in behavior and in ex- 

 ternal appearance are the arctiids. Compsilura shows marked par- 

 tiality for the species noted below. 



The yellow-bear caterpillar (Diacrisia virginica Fab.) and the 

 salt-marsh caterpillar (Estigmene acraea Dru.) are both common 

 species and, although solitary, are often found in abundance. They 

 have a long period in the field, from June until November, and a 

 great variety of food plants. Both are favorable to Compsilura, 

 particularly the former, it being without doubt one of the most 

 acceptable winter hosts. 



The tussock caterpillars Halisidota caryae Harr. and Halisidota 

 tessellaris S. and A. 15 are gregarious. They are general feeders and 

 are occasionally reported as injurious. There is but one generation, 

 the insects pupating in the fall and passing the winter in that stage. 

 Several of the collections have given hymenopterous parasites, especi- 

 ally those of tessellaris, but there are few records of Compsilura. Of 

 the two species, caryae is the most favorable. 



Euchaetias egle Dru. is also gregarious but, unlike the species of 

 Halisidota referred to above, its food plants are limited and it has 

 never been found by the writers on anything but milkweed. In New 

 England it is apparently single brooded; the larvae are usually 

 found in August and September, pupating during the latter month 

 and hibernating in that stage. There are a number of parasites 

 both hymenopterous 'and tachinid, the latter perhaps being the more 

 common. Not only does this species serve as an admirable alternate, 

 but it is also an excellent hibernating host. Four of the five tachinids 

 often bred from E. egle are the same species as those secured from 

 Hemerocampa leucostigma; that is, Compsilura, Tachina mella, 

 Phorocera claripennis, and Fronting frenehii. 



Several other species of this family, solitary in nature, and as yet 

 undetermined, have yielded the parasite. On the other hand, certain 

 species previously cited are for some reason or other seemingly un- 

 suitable. 



NOCTUIDAE, AGARISTIDAE, AND PYRALIDAE 



In the family Noctuidae are found the most divergent forms both 

 in behavior and in external appearance. Species belonging to the 

 genera Apatela, Arsilonche, Mamestra, Catocala, Nadata, Euthisa- 

 notia, Calpe, Pyrophila, Plathypena, Scoliopteryx, Autographa, 

 Cirphis, Plusiodonta, and Rhodophora have all yielded Compsilura. 



Only one of these, however, Autographa brassicae, has been at all 

 constant in its abundance; and, although Compsilura has been oc- 

 casionally reared from it, there is little to be said in its favor. In 

 the collections, it is always closely associated with Pontia rapae and, 

 like that species, has but few parasites. 



Apatela americana Harris is rather a common species, but it is 

 never received in large numbers. It is usually found late in the fall 

 feeding upon maple, oak, and other growth. It is solitary and passes 

 the winter as a pupa. Compsilura and Tachina mella have been 



" Halisidota tessellaris is perhaps found more often, in the last stages, as a solitary 

 larva. 



