STATES OF INSECYS. (Pupa.) 243 
which they may be discerned, and separated with the 
point of a pin*. In proportion as these acquire consist- 
ency, and are more and more developed by the absorp- 
tion of the surrounding fluid, they occupy its place, and 
fill up the cavity of the puparium. The rest of this fluid 
passes off by transpiration>. Reaumur is of opinion that 
it is from the epiploon, or corps graisseuz, that this matter 
is prepared, which he regards as analogous to the white 
ofan egg‘. In coarctate pupe the included animal, or 
the pulp that contains its germes (in which the limbs and 
body at first are not discernible), fills at this period the 
whole skin-cocoon; but in proportion as the above eva- 
poration takes place, and the consolidation of the body 
and parts proceeds, it shrinks at each end, so that when 
near assuming the imago, a considerable cavity appears 
both at the head and tail of the cocoon4. At this period 
of its existence, from the quantity of fluid included in the 
puparium, the animal weighs usually considerably more 
than it does when become a perfect insect * 
The exterior integument or skin of pupze, which is usu- 
ally lined with a very thin white pellicle, is of different 
consistence in different orders. In the Coleoptera and 
Hymenoptera it is, with a few exceptions, of a soft and 
membranous texture; in the Lepzdoptera (especially those 
that are not defended by cocoons), and Diptera, it is more 
rigid and harder, being either coriaceous or corneous. 
Lepidopterous pupze, however, are not excluded from 
* N. Dict. d’ Hist. Nat. vii. 57. > De Geer ii. 105. 
© Reaum. ti. 428—. 
* Swamm. Bibl. Nat. Engl. Tr. ii. 32. ¢. xli. f. 2, Comp. Reaum. 
IV. ts XKVENeN Ne 
* Thid. i. 144, 
