58 TRANSFORMATIOX'S OF INSECTS. 



during these changes, the whole internal lining of the alimentary- 

 canal also comes away with the skin, as was formerly noticed by 

 Swammerdam, and repeatedly observed by ourselves and others. 

 The lining of the mouth and gullet, and that of the mandibles, is 

 detached with the covering of the head, and that of the large intes- 

 tines with the skin of the posterior part of the body ; and besides 

 these the lining of the tracheal tubes comes away. The lining of 

 the stomach itself, or that portion of the alimentary canal which 

 extends from the termination of the oesophagus to the insertion of 

 the so-called biliary vessels, is also detached, and becomes com- 

 pletely disintegrated, and appears to constitute part of the mass 

 voided by the insect on assuming its imago state. Herold, how- 

 ever, has denied that this change ever occurs in the alimentary 

 canal, and says that in the tracheae it takes place only in the 

 larger stems. But Swammerdam states that he saw it in the larva 

 of the rhinoceros beetle, Oryctcs nasicornis, which sheds both the 

 lining of the colon and of the delicate as well as larger branches of 

 the tracheae ; and Bonnet had witnessed a similar occurrence. 

 Burmeister has also seen it, both with respect to the intestine and 

 tracheae, in some of the Libellulce ; and we now add our own 

 testimony to the fact of its occurring, not simply at the extremities 

 of the canal, but throughout its whole extent, as we have distinctly 

 seen during the changes of the nettle butterfly, Vanessa iirticcB. 

 It is more distinctly observed when the larva is changing into the 

 pupa state than at any other period, although we believe that it 

 really does take place at every change of skin. Hence these 

 changes are of the greatest importance to the larvs, which often 

 perish during their occurrence. They are undergone by all larvae 

 which possess the true organs of locomotion, but it has been 

 questioned whether they are common also to the apodal or foot- 

 less kinds, more particularly to those which constantly remain in 

 the same locality until they have changed into pupa^, or nymphs. 



" Reaumur and Huber state that the larva of the common hive- 

 bee does not change its skin, but only grows larger. Swammerdam, 

 on the contrary, asserts that it does, and also that he has observed 

 the same thing in the alimentary canal of the hornet. Burmeister 

 believes that it does not take place, and states positively that 

 the larva; of Diptcra do not moult. We have watched for these 



