STATES OF INSECTS. 275 



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 ?msi- 

 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 lepidopterous or dipterous insects, 

 which are without elytra, to make their way out of such 

 situations, without irreparable injury to their delicate 

 wings. Many of these, therefore, while still within the 

 hard case of the pupa, have the precaution, a few days 

 previously to their exclusion, to force themselves up to 

 the surface of the earth, or, when they reside in the in- 

 terior of trees, to the entrance of their hole. This is ef- 

 fected by a successive wriggling of the abdominal seg- 

 ments, which in several species, of the Coleoptera, Lepi- 

 doptera, and Dipt era orders, for this purpose, as has 

 been more than once observed a , are furnished with 

 sharp points (adminicula), admitting a progressive, but 

 not a retrograde motion. The puparia of the great goat- 

 moth (Cossus lignipcrda) may be often seen projecting 

 from orifices in willow-trees ; and those of the common 

 crane-fly (Tipida oleracea) from the surface of the earth, 

 to which they have thus made their way from a depth of 

 several inches. 



In all the preceding instances the exclusion of the per- 

 fect insect is complete, as soon as it has withdrawn itself 

 from the puparium. But to a very large number, even 

 after this is effected, the arduous task still remains of 



' See above, p. 255—. and Vol. II. p. 301—. 

 T 2 



