148 SATURNIA MYLITTA. 
too heavy to crawl in search of their food with 
their back up, as is usual with most caterpillars, 
but traverse the branches suspended by the feet. 
(See Plate XV. fig. 2.) 
When the caterpillars are ready to spin the cases 
in which they are to pass the chrysalis state, each 
of them connects, by means of the recent glutinous 
filament of which the case is made, two or three 
leaves into an exterior envelope, which serves as a 
basis to spin the complete case or cocoon in ; be- 
sides, the case is suspended from the branch of the 
tree in a wonderful manner by a thick, strong, con- 
solidated cord, spun of the same material, from the 
bowels of the animal. (This pedunculated cocoon is 
represented on Plate XV. fig. 3.) This case is of 
an exact oval shape and exceeding firm texture ; in 
it the animal remains dormant and perfectly pro- 
tected for about the space of nine months, viz. from 
October till July, so that they make their appear- 
ance in time for the caterpillars to come into exist- 
ence when Providence has furnished them with the 
greatest plenty of proper food, viz. during the 
months of August, September, and October. When 
the insect is prepared to make its escape and be 
changed to its perfect state, it discharges from its 
mouth a large quantity of liquid, with which the 
upper end of the case is so perfectly softened as to 
enable the moth to work its way out in a very short 
space of time; an operation which is always per- 
formed durinfj the nio;ht. 
The perfect insect, according to Dr. Roxburgh, to 
