62 ARGYNNIS PAPHiA. 



than the others ; but now this pair began gradually to 

 grow, and in fifteen minutes were far longer than ever, 

 and in another half hour all the other spines had grown 

 considerably, both in length and rigidity; after this 

 the larva remained still for two and a half hours longer. 



The second larva gave me an opportunity of verify- 

 ing these observations on the 27th of May, commenc- 

 ing its last moult at 5 p.m. on that day, and behaving 

 in precisely the same fashion ; when I saw the front 

 legs held back and again dropped forward with the 

 natural motion of relief, after being freed from the 

 old skin, I was reminded of the familiar manoeuvre of 

 one's being helped off from behind with the sleeves of 

 a tight overcoat. 



The second larva had fixed itself on only a part of 

 a leaf, too narrow to admit of any stepping forward, 

 but it knew how to meet this difficulty, for when the 

 sloughing arrived at the first ventral prolegs, the larva 

 fidgeted a little with the anterior legs, but finding 

 nothing they could touch, and remembering that no 

 advance was possible, it kept its place until the final 

 moment came, and then disposed of the difficulty by 

 arching the hinder part of the back convexly down- 

 wards from the leaf, and with a strong effort pulled 

 out the anal prolegs by a downward, not a forward 

 motion. 



The largest larva previously noted made enormous 

 meals for the last ten days, freely exposing itself on 

 the violet plants ; but towards evening, on the 7th of 

 June, it became restless, and wandered actively over 

 the plants, the earth, and the protecting glass cylinder, 

 impatient of confinement, and late at night found its 

 way to the leno covering at the top. Next morning it 

 was still there, but much shortened, and engaged at 

 intervals in adding to a layer of silk already partly 

 spun ; in the afternoon it turned itself round, so as to 

 insert the anal proleg hooks in the small tuft of silk 

 prepared in one spot, deliberately testing the strength 

 with each foot in turn by a visible pull, the ventral 



