12 THE COMMONER BUTTERFLIES. 



while there are several instances known where caterpillars 

 have lived over two winters and might therefore take from 

 eighteen to twenty or more months for their larval ex- 

 istence alone. 



8. How THE Chrysalis Hangs. 



In making its preparation for its final moult, when the 

 change to chrysalis is to take place, the caterpillar proceeds 

 in exactly the same manner as in preceding moults, except 

 that it spins more silk and, in addition to the carpet on 

 which it stands, adds other strands of a special nature, 

 according to the method in which the chrysalis is to swing. 

 The chrysalis is provided with special hooks at its posterior 

 end with which to engage the silken pad jDrepared for it, 

 excepting in the case of a few which change on the surface 

 of the ground. 



One mode of suspension is to hang j^endent by the tail 

 alone from a pad of silk. Generally free to swing with 

 every jar or breeze, the more so as the pad is usually more 

 or less loosely woven, there are some in which the hooks 

 are distributed over a more or less elongated area, and, the 

 caterpillars having constructed a more compact pad, the 

 attachments are firmer and more extended, so that tlie 

 chrysalis may be more or less rigid and even hang in a 

 position by no means vertical but inclined strongly toward 

 the horizontal. 



The movements of chrysalids of the pendent type are 

 not confined to the looseness of attachment of the hooks 

 or the nature of the web to which they cling, but in all 

 there is more or less capability of motion by the sliding of 

 the abdominal joints ..pon one another, and the chrysalis 

 may thus effect voluntary motion, sometimes, when dis- 

 turbed, of an extraordinarily active kind. Some chrysalids, 

 moreover^ make slow periodic diurnal movements, helio- 



