218 THE entomologist's record. 



the larva eats the cast skin, except the head, but I think it is the case 

 that it does not specially eat up the leaf with the silken carpet on 

 which it has rested, as our Cerurae invariably do when possible. 



I had the good fortune to observe one specimen throwing off its 

 larval skin and assuming the pupal state ; and whilst I saw several 

 things that are now well known and understood, there was one 

 circumstance I noted that was quite new to me, as I had never seen 

 it before, nor have I read of it. The pad of silk, to which the larva 

 suspends itself, is made in a few hours ; the actual pad is made by 

 the larva withdrawing its head from the surface, and so making a 

 free loop of silk, longer than is necessary to reach to the point of 

 surface to which it returns, and the repetition of this process gradu- 

 ally forms the pad ; it is always so placed that the larva shall swing 

 clear of all surrounding objects, and never, as many Vanessid larvje 

 will, so that the pupa can touch a vertical surface. It has a certain 

 amount of surrounding spinning, usually apparently with no other 

 object than as standing room for the larva whilst spinning the pad, 

 but in one instance, when the suspension was beneath a leaf, certainly 

 tending to prevent the leaf falling oft' by spinning the petiole to the 

 twig. I never happened to see how the larva made sure of where the 

 pad was when it secured itself thereto with its anal claspers, and it 

 must fall to the suspended position immediately, as I never saw one 

 with its claspers in position on the pad and still holding by the 

 ventral pro-legs, a position held for many hours by most Vanessid 

 larvae I have noticed. As soon as suspended, it curls itself up into a 

 ring, with the mouth to the under surface of the 8th abdominal 

 segment ; this position is maintained for two or three days (in my 

 room, possibly less when at large in a warm exposure). When ready 

 to change, the coloured anal appendages are visible through the 

 larval skin. The first actual steps towards the moult are very slight 

 and slow in progress ; a certain amount of movement is visible by 

 depression or contraction of segments, somewhat rythmically, and 

 apparently, as all these movements are, vermicular, that is, passing 

 from segment to segment. During several hours, however, the results 

 are slight, just as the movements have been : they consist, so far as 

 can be seen, in a few white lines under the first and second, and 

 dorsally on the terminal, abdominal segments, as well as a few in 

 front of the second segment. These indicate places where slight folds 

 have occurred in the effete skin, and probably indicate that the 

 operations of the past few hours have been more important thaji 

 appears, by making the skin everywhere free from the pupal skin 

 beneath, breaking down any remaining cellular attachments, and 

 leaving nothing between the old and new skin but a little fluid. By 

 this time the head of the larva is opposite the sixth abdominal seg- 

 ment, and not quite touching it, so that only a little straightening 

 has taken place. More active (apparently) movements now occur, 

 strictly vermicular in character, that is conmiencing at the anal seg- 

 ment which contracts, and passing forward to segment after segment ; 

 after five or ten minutes the larva is |_-shaped, that is, the thoracic 

 segments are now horizontal, and the head far removed from the 

 front of the abdominal segments. It is now obvious that the 2nd and 

 3rd thoracic segments are enlarged, a change that had already pro- 

 gressed during the first stage ; the first thoracic is small throughout, 



