146 Dr. T. A. Chapman on Heterogyna penella. 
reverse the process of emergence; these movements, 
however, pass backwards along the posterior surface and 
past the anal extremity, and forwards along the ventral 
surface. The full rounded extremity of the moth main- 
tains its apposition with the dorsal jaw of the pupa case, 
which it glides along until it comes over the opening into 
the pupa case, into which it then goes by an ordinary 
vermicular movement. 
The moth is thus replaced exactly into its former 
position in the pupa, the elastic jaws resuming their 
natural relations, and appearances are almost precisely as 
if the moth had never emerged. As a matter of fact, the 
dorsal plate of the prothorax overlaps the head, thus 
closing the opening more completely, but even so, a 
close examination is necessary to recognise the difference 
from an unemerged pupa. 
The process of oviposition then commences and ap- 
parently lasts for some days, the denser bulbous part of the 
pupa case being packed with eggs, the moth acting as a 
stopper over them in the upper part. 
Though little more than a bag of eggs, the female 
imago has a well-developed set of cutaneous muscles, in 
longitudinal, transverse and diagonal bundles, very much 
the same as may be demonstrated in the larva, and as are 
figured by Lyonet and others in the larve of other 
Lepidoptera. 
The eggs are ovoid, yellow and delicate in texture, 
not unlike those of Zygenas and, like them, have a 
transparent space at one end. They do not appear to 
be laid in any particular order or arrangement, but adhere 
so firmly to each other and to the pupal shell, that any 
attempt to individualise them only results in smashing 
them. If exposed, as by breaking the chrysalis case and 
removing the moth, they very soon dry up and shrivel. A 
chief object, probably the chief object, of the remarkable 
modification of structure and economy in the female of 
Hf, penella, is evidently the protection of the ova from 
predaceous enemies and parasites, no doubt, but most 
especially from the danger of desiccation. That this is an 
object most necessary to be attained, will appear when we 
remember the high temperature and arid character of the 
country where the species is most plentiful, such as the 
neighbourhood of Digne. It seems to be very effectually 
carried out by the thick, elastic, gutta-percha-like texture 
