265 
ves till the following spring I can only make suggestions 
having no evidence to go upon. Most probably a number 
of species pass the winter as larvæ or fully developed 
imagines of the last generation of a year, in the eggs of 
their host, but nevertheless the possibility that the imago 
hibernates in the cracks of bark or similar places it not 
excluded. To discover these minute insects in their win- 
ter quarters is by no means easy and if at any time this 
point is made clear it will no doubt be discovered by 
pure accident. Personally I am most inclined to believe 
that the winter is passed in the eggs of the host. 
At present the life history is known only of Poropoea 
(Silvestri: Boll. Portici 1909), Trichogramma (Silvestri: 
Boll. Portici 1909; Gatenby: Quart. Journ. Micr. Sci. 1917) 
and Prestwichia (Henriksen: Ent. Medd. XII 1918). 
Very little is published with regard to the anatomy 
of these insects. Aurivillius, I. c. p. 253, remarks that the 
muscles of the thorax in Oophthora reach far into the 
abdomen. They have, however, proportionally long wings 
and it is only natural that the muscles to move these 
large instruments if movement must be very powertul as 
well as the corresponding Postphragma being strong and 
inclined into the abdomen. This can also be observed 
with several other species when highly magnified and by 
the aid of falling light. Drawing No.1 in Aurivillius gives 
a very good view of how these muscles appear. The ex- 
terior of these insects offers nothing unusual when com- 
pared with the other Chalcids. The mandibles are, as far 
as I have been able to see, always provided with three 
teeth, the outer and the median tooth are acute and di- 
stincly chitinised and the inner one rather indistinct. Maxil- 
lary palpi always two jointed, with a long hair on the 
basal joint. Tarsal joints and feet generally speaking uni- 
form in the whole group (see Figures). 
Sometimes it is exceedingly difficult to distinguish the 
sexes, and very often the only means is by examining the 
