DEVELOPMENT OF CYNIPID HYPERPARASITES AT5 
parasitized by such a form as Lygocerus (Proctotrypidae) 
by chance, 8 per cent. of the former should be destroyed ; 
while where the incidence of parasitization by Chalcids, such 
as Asaphes, is as high as that of Lygocerus, this rate 
of mortality must be doubled. The above figure for Cynipidae 
is hypothetical, though, as it is based on examination of much 
material, it 1s probably not too low. That for Lygocerus 
was found to be the actual rate in certain instances (10). It 
is difficult to estimate the mortality accurately, because the 
host, if subsequently reparasitized, rapidly decomposes, and 
any endoparasite that it may contain soon becomes unrecogniz- 
able. Moreover, the bionomical relations of the different 
hyperparasites are so intricate that the chances of survival 
of any particular case are difficult to compute. Thus Charips 
actually lessens its own chance of survival, for the effect of 
its parasitization is to arrest the metamorphosis of the host, 
and thus maintain it in the optimum condition for oviposition 
by Lygocerus or Asaphes. Hence in the hypothetical 
case given above the number of Aphidius larvae parasitized 
by Charips and reparasitized by Lygocerus would 
probably be larger than that parasitized by Lygocerus only, 
and the mortality of the first parasite would actually be higher 
than the figure given. To this mortality from reparasitization 
I attribute the fact that from collections of parasitized aphides 
made in the field there were proportionately more Cynipid 
emergences in June than in July. Most of the hyperparasites 
obtained from later collections were Chalcids or Proctotrypids 
(Lygocerus) ; and the inference is that the later broods of 
Cynipidae suffered from a second parasitization of their hosts 
by other hyperparasites. 
SUMMARY. 
1. Bothryoxysta curvata, Kieff., Charips victrix, 
Hartig, and Alloxysta erythrothorax, Westw., are 
hyperparasites of aphides through Aphidius (Braconidae). 
2. Reproduction may be either sexual or parthenogenetic. 
3. The egg is laid in the haemocoele of the host larva before 
