234 STATES OF INSECTS. (Larva.) 
adult insect cannot yet be detected. Nature requires 
more time for their elaboration, or at least for the ap- 
pearance of their outline, and to consolidate them. This 
pulp first takes an oblong form (Boule allongée Reaum.), 
and afterwards that of the insect it is destined to give 
birth to?. The skin of the larva also serves for a cocoon 
to the pupze of male Coccz>, The grub of the genus An- 
threnus, so destructive to our cabinets of natural objects °, 
when it assumes the pupa does not quit its skin, but only 
splits it open longitudinally on the back, and when it 
becomes an imago makes its exit through the orifice 4. 
Some Lepidopterous larvae even (Alucita pentadactyla, 
Callimorpha rosea, &c.) assume the pupa state within 
their last skin *. 
When a larva has finished its cocoon,—which with 
some species, that proceed so earnestly as though they 
had not a moment to lose, is the work of a few hours, of 
a N. Dict. d’ Hist. Nat. xvi. 269—. xxii. 76. 
> Reaum. iv. 32. The author here quoted asserts that the grub of 
Ichneumon Larvarum, L. retains its skin, which, he says, is so trans- 
parent that the form of the nymph can be seen through it. Ibid. ii. 
447. De Geer, however, found that this really did cast its skin, 
which is so transparent as to be scarcely visible, by pushing it gradu- 
ally towards the anus, where it soon dries up and cannot then be dis- 
covered. De Geer il. 893—. According to Résel the same circum- 
stance attends the transformation of Coccinella renipustulata, Illig. 
(C. Cacti, Ent. Brit.), which at first perplexed him not a little. It is 
probable that in this case the retention of the skin was accidental ; 
for some of the grubs of a Mycetophila, the transformation of which 
I observed, became pupz within their last skin, while others wholly 
disengaged themselves from it. The cause of this variation, I con- 
jectured, arose from the former being too weak to extricate them- 
selves from the skin. 
‘© See above, Vor. I. p. 240. 
4 N. Dict. d Hist. Nat, ii. 161. * Pezold. 102. 
