1910] Timberlake — Aphidiine Parasites of Aphids 127 
larva, enter it and finally destroy it. Only one Encyrtid was reared 
from a cocoon. 
From a number of cocoons collected from rose-bushes recently 
placed out of doors at the greenhouse, there was reared a species of 
Xystus of the family Figitide, and also a species of Pteromalid of 
the genus Asaphes. 
While making observations on Praon at the greenhouse we found 
another species of the Aphidiine rather abundant and confining its 
attack principally to the above-mentioned species of aphid on carna- 
tion, though occurring less commonly on the rose-aphid. This 
species is possibly the European Aphidius rose Hal. 
Encouraged by the interesting results with Praon we started 
reproduction experiments with this species and soon secured the 
early stages. The first stage larva proved to be far less specialized 
than that of Praon as it lacks the dorsal combs of bristles, and the 
tail-like appendanges. A description with drawing is appended 
with that of Praon. 
Specimens of the aphid host were also collected at the greenhouse 
and dissected. The results are exceedingly instructive and may be 
tabulated as follows: 
20 full-grown agamic female aphids dissected. 
15 of the 20 or 75% were parasitized.’ 
10 of these 15 proved to be superparasitized.* 
5 contained two larve (in one case a larva and an egg). 
3 contained three larve (in one case a Praon larva). 
1 
1 
contained four larvee. 
contained five larve. 
Adding up the number of larve or eggs found in these 15 aphids 
we have a total of 33, only 15 of which could have ever reached 
maturity, leaving 18 to perish, more than three times as many needed 
to destroy the five unparasitized aphids, if the eggs had been dis- 
tributed more equitably. 
These results are the more remarkable when we consider that 
oviposition took place under normal conditions in a well-lighted 

1Two of the fifteen parasitized aphids contained larve so far advanced that 
they had already destroyed every trace of any supernumerary larve that might 
have been present previously. 
2See W. F. Fiske’s paper, Superparasitism: an important factor in the natural 
control of insects. Jour. of Econ. Ent., vol. 3, no. 1, pp. 88-97. 
