ARGYNNIS PAPHIA. 61 



moult, fixed belly upwards to the uuderside of a leaf on 

 the 20th of May, and remaining quite still until noon of 

 the 25th, when I noticed it moving its anterior legs a 

 little free from the leaf, a circumstance which claimed 

 my whole attention ; it was but a slight movement and 

 was repeated at intervals of about half an hour, until 

 between two and three o'clock in the afternoon, when 

 it began to stretch its first segments downwards from 

 the leaf, making the fore part of the back concave, and 

 then presently gently reversing the movement. It con- 

 tinued thus at short intervals to increase the stretching 

 curve of the body so much, that by ten minutes past 

 three its hold on the leaf was retained only by the fourth 

 pair of ventral prolegs and the anal pair, when sud- 

 denly the skin snapped asunder close to the head, with 

 quite a shock to the larva, which instantly returned 

 its ventral prolegs to the leaf, while the elastic skin, 

 relieved of its tension, was itself from the impetus of 

 the rupture gliding backwards. The anterior legs were 

 held back until divested, and then returned forwards 

 to their natural position one after the other, but kept 

 just free from the leaf, each pair being elevated in 

 unison for a moment, and let fall, as though to test 

 their complete freedom ; otherwise the larva remained 

 passive, the skin only continuing to move backwards, 

 and whilst passing the ventral prolegs, each foot in 

 turn was lifted up out of it, and then replaced on the 

 same spot of the leaf, and when the old skin had 

 shrivelled up together at the end of the body, the 

 larva, with all the ventral prolegs, took two steps 

 forwards and drew forth the anal pair free. 



At the first breaking of the skin the head became 

 exposed, with the old head-piece adhering to the parts 

 around the mouth, but now, at last, the larva gave its 

 head a sudden twist or two, and the old piece fell off ; 

 from the rupture of the skin to this final riddance the 

 operation occupied nearly ten minutes; the spines were 

 all uncovered in a remarkably small and rudimentary, 

 wet and flaccid condition, the front pair even smaller 



