Caterpillars

Abstract

LAST year (NATURE, vol. xv. p. 7) I communicated the result of some experiments on the caterpillars of Pieris brassicœ from which it appeared that, when these are artificially converted from succincti into suspensi by cutting the loop before the exclusion of the chrysalis, a certain number (a third or fourth of the whole succeed in attaching themselves to the silk by the hooks in the tail of the chrysalis in the manner of the true suspensi. I have repeated the experiment this year with a like result, and I have also had the satisfaction of witnessing the process of successful exclusion, and comparing it with that of the chrysalis of Vanessa urticœ. The method is essentially the same, except that the rapid and assured precision with which the Vanessa chrysalis thrusts up its tail and lays hold upon the silk, is replaced in Pieris by long and laborious efforts, as if the tail were just a little too short to reach the silk.