158 Mr. R. J. Ash ton's Note 



relative merits and credibility of the before mentioned investi- 

 jT.itors, and thus the question remains at the present moment 

 unsettled, though capable of the easiest and most conclusive 

 ascertainment imaginable. Such being the case, I take the liberty 

 of stating the observations which I have lately made on tliis sub- 

 ject, and which in fact drew my attention to tlie dispute I have 

 just detailed. Happenino- to detect a caterpillar of Sphinx Li- 

 gustri in the act of changing ats skin, I made it go through the 

 operation in my hand, so as to watch its progress more minutely. 

 As soon as the external integument was, after much writhing and 

 contortion, completely slipped off, as I found it still adhered 

 loosely to the insect, I touched it with my penknife to cause it to 

 separate from it, when I found that it was yet connected with it 

 in some essential manner, and, on a closer examination of the 

 cause, I perceived at once that it was occasioned by the mucous 

 coat of the intestinal canal, which was in the act of being gradually 

 passed out at the anus, and being in intimate connexion with the 

 recently shed external integument, or, according to Burmeister, 

 merely a prolongatmi thereof, occasioned that attachment of the 

 old skin to the caterpillar which at first had perplexed me. To 

 this observation I may add, that 1 have since discovered the 

 moulted colon in the skin of a caterpillar of the same species cast 

 off on assuming the pupa state, lying folded up at the posterior 

 end thereof, exactly as described by Svvammerdam. As this my 

 testimony, slightly as it might be thought of by itself, directly 

 establishes the accuracy of such illustrious observers as Svvam- 

 merdam and Bonnet, I trust it will be received as a satisfactory 

 affirmation of the fact of the moult of the lining of the intestine, so 

 unwarrantably denied by Herold. Then as to the moult of the 

 smaller ramifications of the trachea, I am able to give quite as 

 conclusive evidence of the correctness of Swammerdam's account 

 in every particular, and consequently of Herold's inaccuracy. 

 Quite apart from any consideration of the conflicting statements 

 of the above naturalists, I happened to be examining the skin 

 cast by a caterpillar of Sphinx Ligustri on changing into the pupa, 

 when my attention was attracted to the very conspicuous thick 

 whitish bands, which appear, one on each side of the body, nearly 

 its whole length. On a close examination, 1 perceived that these 

 bands were divided into a certain number of equal lengths, one 

 end of each of which was intimately connected with a spiracle, 

 whilst the other end was free and unattached, but from the cir- 

 cumstance of their all lying down in the same direction (viz. from 

 the posterior end towards the anterior), and being of sufficient 



