28° BULLETIN 1487, U. S. DEPARTMENT OF AGRICULTURE 
The adults appear about the middle of May and pass through two, 
and somtimes three, generations annually, the summer generations 
requiring approximately three weeks for development from egg to 
adult. The larvae are ectoparasitic within the host cocoon, and 
always solitary, only one maturing on an Apanteles. Hibernation 
occurs in the form of full-grown larvae in the Apanteles cocoon. 
When reproducing parthenogenetically the species produces males. 
HYPOPTEROMALUS TABACUM (FITCH) 
The species of this genus are apparently always hyperparasitic, 
and are sometimes very destructive parasites of Braconidae. Hypop- 
teromalus tabacum, a widely distributed North American form, has 
appeared commonly among the species reared from Apanteles mela- 
noscelus, although it does not rank with Eurytoma appendigaster, 
Hemiteles tenellus, Dibrachys boucheanus, or Dimmockia incongruus 
in point of abundance. In the laboratory the writers have found it 
to oviposit much more readily than the closely related Habrocytus 
in Apanteles cocoons, but field collections of cocoons indicate that 
there is little difference in effectiveness between the two. 
Adults emerge late in May and sometimes parasitize the first 
brood of Apanteles quite extensively. The larva develops as a 
solitary ectoparasite within the cocoon and matures rapidly; only 
14 to 23 days elapse between oviposition and the emergence of the 
adult. Despite this rapid development, however, there are in general 
only two generations annually. Second-generation A. melanoscelus 
cocoons which are attacked in July usually carry the species over the 
winter in the form of full-grown larvae. 
HYPOPTEROMALUS INIMICUS MUESEBECK (27) 
This species has been obtained only in relatively small numbers, 
and up to the present time has been of but minor importance in check- 
ing the increase of Apanteles melanoscelus. In habits and life history 
it agrees with Hypopteromalus tabacum. 
EUPTEROMALUS NIDULANS (FOERSTER) 
Kurdiumov (22) has shown that the species discussed under the 
name Pteromalus egregius Foerster by Howard and Fiske (19) is 
Eupteromalus nidulans (Foerster). Although during the height of 
the brown-tail moth epidemic in New England it was abundantly 
found acting as a primary parasite of the small hibernating cater- 
pillars of that pest, this species appears at present. to be more com- 
monly hyperparasitic, developing within the cocoons of various 
Braconidae. The writers have never obtained it in large numbers 
from Apanteles melanoscelus, however. In fact, during the years 
that the hyperparasites of this Apanteles have been closely observed, 
it has been one of the least important among these species. It seems 
to prefer for oviposition cocoons that are more delicate and of finer 
texture than those of A. melanoscelus. A. lacteicolor Viereck, the 
brown-tail moth parasite, is attacked to a considerable extent in 
the field. And in the laboratory the writers have been more suc- 
cessful in breeding it upon cocoons of A. glomeratus L., A. hyphantriae 
Riley, and A. ewchaetis Ashm. than upon those of A. melanoscelus. 
