STATES OF INSECTS. (Pupa.) 273 
pupz of the gay-winged Trypeta Cardui* are inclosed. 
That it is designed by Creative Wisdom to answer this 
sole purpose seems proved, from its disappearing soon 
after the disclosure of the fly, whose head shortly becomes 
all alike hard. Reaumur suspects that it may also be 
intended to promote the circulation of the insect’s fluids; 
but to me his reasons appear not conclusive». In one 
instance a mode still more unexpected obtains. The il- 
lustrious naturalist just named found that the fly which 
proceeded from one of the rat-tailed grubs (Helophilus), 
had actually the power of completely reversing its situa- 
tion in its narrow case; and that it then employed its 
tail in pushing off the lid, which other species remove by 
means of their head ¢. 
The extrication of insects whose pupe are above 
ground, like those of butterflies, many beetles, flies, &c., 
is comparatively a simple operation. But what, you will 
ask, becomes of those species whose pupz are concealed 
deep in the earth, or in the heart of the trees on which 
their larvee have fed? Of this you shall be informed.— 
Coleopterous insects disclosed from pupze thus circum- 
stanced, wait until their organs have acquired strength, 
and their elytra are sufficiently hardened to protect their 
filmy wings from damage in forcing their way through 
the earth or wood which covers them. Thus Oryctes nas?- 
cornis, a rhinoceros beetle common on the Continent, is 
a full month before it reaches the surface of the earth, 
after quitting its puparium. But it is evident that no 
delay would enable Jepidopterous or dipterous insects, 
* Reaum. iii. ¢. xlv. f. 12—14, 
> For this whole account, see Reaum. iv. Mem. viii. 
© Ibid. 472. 
VOL. IIl. ab 
