DEFORMED INSECTS. 349 



by a silken cord, is prevented from becoming duly 

 expanded, and when the insect is excluded it is found 

 to be deformed. This might by some be imagined 

 to be a mere theoretical view deduced from physio- 

 logical reasoning; but we can prove it by specimens 

 of moths arid butterflies which we have reared. A 

 colony of the brown-tail moth (Porthesia auriflua), 

 which we reared during the summer of 1829, spun in 

 the corner of a nurse-box a common web of several 

 chambers for containing the pupae. One of these 

 chambers being accidentally torn, a pupa fell upon 

 the earth in the bottom of the box, and in due time a 

 female moth was produced from it ; but she never 

 succeeded in expanding her wings, which remained 

 till her death shrunk, rumpled, and totally useless for 

 the purpose of flying, though in every other respect 

 she was full grown, and deposited in the box a group 

 of fertile eggs, covered with down from her tail as 

 neatly as was done by her sisters of the same brood. 

 In the summer of 1825, the chrysalis of a small tor- 

 toiseshell butterfly ( Vanessa Urticce) lost its hold of 

 its silken suspensory, and fell upon the pasteboard 

 bottom of a nurse-box, resting in a sort of angular 

 position, so that the case of the upper wing on the 

 left side pressed upon the box with the whole weight 

 of the chrysalis above it. When the butterfly made 

 its appearance, it expanded its wings as usual, but 

 the wing upon which it had rested was not half the 

 size of the one on the right side which had lain 

 uppermost. Another of the same brood had by 

 some cause not grown so large in the caterpillar 

 state as the rest. It was transformed, notwithstand- 

 ing, into a chrysalis, which appeared healthy and 

 well formed; but when the butterfly appeared, though 

 it did not differ from the usual appearance, its wings 

 never expanded a single hair's breadth, and remained 

 VOL. vr, 30 



