222 STATES OF INSECTS. (Larva.) 
other hand the silk of the cocoons of Saturnia Spint 
and of several foreign species is as thick as a hair. 
With regard to the texture of their cocoons—in some, 
as in that of the silk-worm, the threads are so slightly 
glued to each other as to separate with facility; but in 
that of the emperor-moth just mentioned they are inti- 
mately connected by a gummy matter, furnished, as 
Reaumur conjectures, from the anus*, with which the 
whole interior of the cocoon is often plastered. Some, 
as that of the silk-worm, are composed of an exterior 
loose envelope, and an inner compact ball; others have 
no exterior covering, the whole cocoon being of an uni- 
form and thick texture. The larva of Cossus Robinie 
- Peck, in spinning its cocoon, makes the end next the 
opening to the air, by which the imago is to emerge, ofa 
slighter texture than the rest of it. The exterior case 
is sometimes, as in Dasychira pudibunda, very closely 
woven, so as to resemble a real cocoon®: its form is 
usually adapted to that of the inner one; but in some 
which fix them under flat surfaces (D. fascelina, Euprepia 
Caja), it resembles a hammock*. Cocoons of a close 
texture have generally no orifice in any part; but that of 
Eriogaster lanestris is spun with openings, as if bored 
from without, the use of which, however, does not seem 
to have been ascertained °. 
Many silken cocoons are of so close a fabric, as, when 
finished, entirely to conceal the included insect; but a 
very considerable number are of a more open texture, 
composed of a much smaller quantity of silk, and that 
* Reaum. i. 503. » Peck on Locust-tree Insects, 69. 
* Bonnet ii. 260. 4 Sepp. iv. é. ii. ft 4. 
“ Brahm. Ins. Kal. 289. 
