of cei'tain lepidopterous larva and pupce. 41 



never rested in another posture, but I am certain that 

 this was not commonly the case. Next year I hope to 

 be able to settle the point by further and more extended 

 observations. 



When the larvae of E. pendularia were about half the 

 full size, and brown in colour, I observed that they were, 

 with hardly an exception, hanging from the under side 

 or edges of the leaves, and that the body was thrown 

 into a spiral of from one to one and a half turns. The 

 head was nearly always downwards, and the caterpillar 

 greatly resembled a brown spiral larva-case hanging from 

 a leaf, — in fact, I thought for a moment that some of 

 these must have been accidentally introduced with the 

 food. I afterwards found that this was a common 

 attitude during rest, and that it was especially main- 

 tained during the long period of quiescence that pre- 

 cedes ecdysis. It was so continuous on this latter 

 occasion, and occurred in so many larvae (I did not 

 notice a single exception), that I thought for a long time 

 that it must be important in producing tension in the 

 old skin. But the attitude occurs at other times, and 

 further, I have never noticed it in other larvae before 

 ecdysis, where the same tension would be as beneficial 

 as in this case. If the object of the spiral attitude be 

 to split the old skin we should expect to see it assumed 

 just before ecdysis, and not maintained for the long 

 period during which the larva ceases to feed. If further 

 observations show that this position is of assistance 

 to ecdysis it will still be true that the larva derives other 

 benefits, in the same way that the usual darkening of 

 colours before pupation is also of protective importance 

 when larvae wander over the ground in search of a spot 

 to bury in. But, as far as my observations have gone at 

 present, I am inchned to think that this attitude is 

 especially maintained on such occasions, because the 

 larvae are then necessarily quiet, and have no reason to 

 give up the protective position. These periods are the 

 only long rests of larval life during which protection of 

 attitude (as apart from colour) can be uninterruptedly 

 kept up, for at all other times there is the constant 

 necessity of feeding and of moving to fresh food, although 

 the danger is frequently averted by such movements 

 being nocturnal. 



The larvffi of E. pendidaria assume the normal atti- 

 tude of Geometry after the last ecdysis, and then usually 



