166 INTERNAL ANATOMY OF INSECTS. 
stances she never attempts to leave the pupa-case in 
which she has been disclosed, but that being there im- 
pregnated by .the male, she there also, apparently after 
the manner of the female Cocci, deposits her eggs, which 
hatching produce young larvae that make their way out 
of the case, and thus seem to originate without maternal 
interference a . 
But the most remarkable fact bearing upon this head, 
though as relating to a viviparous insect it does not 
strictly belong to it, is the impregnation of the female 
Aphides, or plant-lice, before alluded to b . If you take a 
young female Aphis at the moment of its birth, and ri- 
gorously seclude it from all intercourse with its kind, 
only providing it with proper food, it will produce a 
brood of young ones : and not only this ; but if one of 
these be treated in the same way, a similar result will 
ensue, and so on, at least to xh&Jifth generation ! ! to 
which period Bonnet, who first made an accurate series 
of observations on this almost miraculous fact, success- 
fully carried his experiments, till the approach of winter 
and the want of proper food forced him to desist c ; and 
Lyonet extended it still further d . It is now generally 
admitted as an incontestible fact, that female Aphides 
a It does not appear to be clearly decided whether the eggs are ex- 
truded from the female, or whether dying immediately after fecunda- 
tion they are hatched within her body. As the young larvae cer- 
tainly are hatched in the pupa (not merely within the exterior case 
of bits of grass, &c, which includes it) which the body of the insect 
must fill, it does not seem easy to conceive how she can find room 
for oviposition ; and yet Von Scheven expressly says that one female 
of Ps.vestita — which being kept from all access to the male actually 
left the pupa-case and wandered about the glass which contained 
them— laid unfruitful eggs. b Vol. I. p. 32, 175. 
c Bonnet i. 10—. d Reaum. vi. 551. 
