1S02.] -'>*7 



and the light, tlio first stago ol' t!io multiiiL;- jirocoss can be seen. The 

 front of the head shows a translucent linear spnce. indicating the separa- 

 tion of the head within, from its outer case. As this space increases, tlie 

 first and second segments of the body show a corresponding enlargement, 

 until the head has been wholly withdrawn from its case, and is covered 

 by the skin of the anterior segments, now much extended from the great- 

 ly increased size of the head.* The color of the larva becomes dull, from 

 the absorption by the body, it is supposed, of the fatty matter which sepa- 

 rated the new skin from the outer, leaving the latter comparatively dry, 

 and in readiness to be cast off. 



The actual molting commences, by a rupture of the skin at its junction 

 with the head case, above. The muscular effort of the larva usually sufii- 

 ces to accomplish this, and to detach the case, but occasionally, it is oblig- 

 ed to resort to violent rubbing against the leaf. If the case should still 

 remain connected by a small portion of the skin, the larva proceeds to 

 extricate its legs, with which it seizes the case, and at once effects the sep- 

 aration ; in no instance is it allowed to remain attiiched. These cases, 

 thrown oft" as they are, by all the Sphin.x larvaj, unbroken and often i-e- 

 taining the original colors, should be careful!}- preserved, whenever the 

 opportunity offers, as interesting and valuable cabinet specimens. Through 

 the opening thus made, the larva, by the alternate extension and contrac- 

 tion of its segments, emerges from its old covering, with a brighter and 

 usually a different coloration, and materially increased size: the operation 

 requires about five minutes for its accomplishment. f 



The molting completed as above, the larva moves backwards a few steps, 

 until it comes in contact with the skin still adhering firmly to the ner- 

 vure, when it elevates the posterior portion of its body over it, and grasps 

 it firmly with its terminal prolegs. In this position, it continues motion- 

 less for about two hours, when it turns deliberately about, and commences 

 to feed upon its old skin, of which it usually leaves not a fragment re- 



••■ It is only at the moltings, that the head, by its release from the confinement 

 of the old case, is capable of eulargeinent, retaining the size which it then receives 

 until the next change. Immediately after a molting, its diameter is greater than 

 that of the body ; before the next molting, less. 



t The molting process, as given us, without qualification, by authors, viz. — the 

 sk'in splits longitudinally along the back, and the caterpillar extricates itself from 

 its old covering, by drawing out the body, leaving all the external visible organs, 

 even the mandibles and palpi, attached to the old skin, — is true of some of the 

 families of Lepidoptcra, but never of the Sphingidce, except in the final casting of 

 the skin, uiion as.-iuming the pupa state. 



