268 STATES OF INSECTS. (Pupa.) 
may see them fill the air; but an hour before or after, 
you will in vain look for one*. So also the silkworm- 
moth and the hawkmoth of the evening primrose (Ma- 
croglossa C!nothere) constantly break forth from the 
pupa at sunrise : and the hawkmoth of the lime (Smerin- 
thus Tilia) as certainly at noon®. Schroeter states, that 
of sixteen specimens of the death’s-head-hawkmoth 
(Acherontia Atropos) which he bred, every one was dis- 
closed between four and seven o’clock in the afternoon ®. 
Before I conclude this head, I must observe, that after 
a caterpillar or gnat has spun its cocoon, it sometimes 
remains for a considerable period before it incloses itself 
in the pupa-case, and casts off the form of a larva. Thus 
the little parasite (Mzcrogaster glomeratus) that destroys 
the caterpillar of the common cabbage-butterfly, remains 
a larva in its cocoon for many months, but it becomes a 
perfect insect a few days after it has put on its pupa- 
rium ¢; and the caterpillars of the great goat-moth (Cos- 
sus ligniperda), if they spin their cocoon in the autumn, 
remain in it through the winter in the larva state; 
whereas, if they inclose themselves in the month of June, 
they assume the pupa, so as to appear as flies in three 
or four weeks °. It is not therefore easy to state precisely 
the age of those pupze which are produced from larvee 
that spin cocoons. 
v. I have not much to say with regard to the sex of 
? Reaum. vi. 486. > Brahm. 423. 421, 
© Naturf. xxi. 75. ¢ Reaum. ii. 423. 
e De Geer ii. 370. It is not certain, however, that De Geer did 
not, in this instance, mistake the winter habitation ofa larva for a 
cocoon intended to shelter the future chrysalis; since Lyonet in- 
forms us that they spin a habitation to pass the winter in. Traité 
Anatomique, &c. 9. 
Ae Sa ee 
