160 INTERNAL ANATOMY OF INSECTS. 
manner of the female Cocci, deposits her eggs, which 
hatching produce young larve that make their way out 
of the case, and thus seem to originate without maternal 
interference?*. 
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’. 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 the fifth 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*; and 
Lyonnet extended it still further¢. It is now generally 
admitted as an incontestible fact, that female Aphides 
have the faculty of giving birth to young ones without 
having had any intercourse with the other sex. How 
are we to explain this most extraordinary fact? Are 
* 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 larve cer- 
tainly are hatched in the pupa (not merely within the exterior case 
of bits of grass, &e., 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. bY Vor. T.p: 32; 174: 
© Bonnet i. 19—. 4 Reaum, vi. 551. 
