AU 
Sy cenis 
VOL. XVII. AUGUST, 1910. ING =uA 


OBSERVATIONS ON THE EARLY STAGES OF TWO 
APHIDIINE PARASITES OF APHIDS. 
By P. H. TrmmBertake, 
Bureau of Entomology, Washington, D. C. 
A few weeks ago some cocoons of Praon were discovered on a 
rose-bush brought to the Gypsy Moth Parasite Laboratory from a 
local greenhouse, and at the suggestion of Mr. W. F. Fiske, the 
opportunity was seized of making a brief study of the early stages 
of this common parasite of aphids. 
Accordingly a small number of the cocoons was secured, and as the 
imagines emerged they were enclosed in a small glass cylinder with 
a sprig of rose and a few aphids. The females were not observed 
to mate with the males, but were frequently seen ovipositing in the 
plant-lice. The oviposition habits are like those of other Aphidiines 
as already described many times. The female bends the tip of her 
abdomen between her legs, and by a sudden trust darts it under her 
head into the abdomen of the helpless victim, completing the act in 
a moment of time. 
By the dissection of parasitized aphids from these simple repro- 
duction experiments, the eggs, first and second stage larve were 
easily secured, and the third stage larva was as readily obtained by 
opening fresh cocoons. 
The eggs are undoubtedly placed one at a time in the abdomen of 
the host, and lie free among the organs and tissues beneath the 
integument. They are minute, ovoid bodies, white in color, of no 
special characteristic form or appearance. Like the eggs of Platy- 
gaster as observed by Marchal’ they double and triple in size before 
hatching. This increase in size is able to take place, probably on 
account of the plastic nature of the chorion, which expands as the 

_ 1 Paul Marchal. Recherches sur le biologie et le développement des Hyménoptéres 
parasites. Les Platygasters. Arch. Zoél. (Paris), Vol. 4, pp. 485-640. 
