DEVELOPMENT OF CYNIPID HYPERPARASITES 461 
Moreover, the arrangement of the cells does not suggest that 
they have arisen by division from the peripheral nuclei. The 
disappearance of the chromatin masses seems to indicate that 
there has been a recent escape of the contents of the blasto- 
coele, but this matter does not appear in the involucre. It 
may be represented by a small mass found in the host’s tissues 
opposite the point marked « in the figure. In any case, though 
Gatenby’s explanation accounts for the appearance of the 
membrane in his own and in Silvestri’s figures, it does not seem 
possible that the extruded matter could, under compression of 
the chorion, take an outline such as that shown in Text- 
fig. 4c. 
The data are too scanty to permit of our forming a definite 
opinion on the origin of the involucre in these Cynipidae, but 
I hope to pursue this subject later when more material is 
available. Gatenby, however, remarks that in some cases 
living nuclei are carried out with the extruded material : 
‘ Curiously enough these fragments seem to live a good while, 
and nuclear changes, such as those undergone in the blastoderm, 
take place in some cases.’ 
Without hazarding an opinion on the different views of 
these observers as regards the Trichogrammatinae, a sugges- 
tion may be made that if the expulsion of live nuclei were to be 
carried further in Charips than it isin Trichogramma, 
these might by division give rise to the membrane. But 
either this division must be very rapid, to develop the involucre 
in the space of two or three hours, or else the initial expulsion of 
the living nuclei must be larger than it appears to be from 
an examination of the material. 
Tue Frrst Instar (Text-fig. 5). 
Dimensions, 0:38 x 0-183 mm. The embryonic membrane is 
ruptured two or three days after oviposition. The newly- 
hatched larva is heavily armoured with dark segmental plates 
of chitin, which render it easily visible through the tissues 
of the host. It possesses a distinct head and thirteen body- 
segments, the last of which terminates in a caudal appendage. 
