^^ AND ^^^i 



JOURNAL OF VARIATION. 



Vol. VII. No. 6. December 15th, 1895. 



The "Basket Caterpillar" and " Bagworm." 



(With Plate). 

 By J. W. TUTT, F.E.S. 



I received in August last, from Mr. Joseph Anderson Junr., of 

 Chichester, a number of remarkable cases, varying from 2J to 2f inches 

 in length, which had evidently been constructed by the caterpillar of 

 some lepidopterous insect. These cases had been sent from the 

 Argentine Republic, and Mr, Anderson informed me that the insect 

 was known there by the name of the "Basket Caterpillar," 



The cases were fastened round a twig [ride, Fig. 1 a ; Fig 3 f). 

 As the full-fed larva crawls along in the manner shown (Fig. 3 ,/'), 

 and evidently does not leave its case to fasten it thus when full-fed, it 

 is clear that the fastening must be done when the caterpillar is inside, 

 and the head towards the fastening. Unless the caterpillar turns 

 round before pupating, it might reasonably be supposed that the head 

 of the pupa pointed towards the fastened end. At the opposite end 

 is a long loose cylindrical silken structure open at the extremities. 

 That the larva does turn round was evident on dissection, for the head 

 of the pupa was turned away from the fastening, and the cast larval 

 skin, head, &c., which had come away when pupation took place, 

 were at that end at which the case is fastened to the twig. I need 

 hardly point out that this is what ordinarily takes place in Fsi/rhc : the 

 species figured in the Plate being evidently not far removed from P. 

 rillosella, and is only insisted upon here to show that the abdomen is 

 not towards the opening at the opposite end when copulation takes place. 



On cutting open a case one sees that it is made of three 

 layers : (1) a smooth inside layer of silk ; (2) a middle layer of 

 short pieces of stick bound together with a little silk ; (3) a smooth 

 outside layer of white silk covering the sticks. Inside the case is the pupal 

 skin, the lower half filled with eggs and with material which I look 

 upon as the dessicated body of the female (Fig. 3 f). 



Taking some of these eggs in my hand, I found that many had 

 already (August) hatched, that, in fact, although they bore every 

 appearance of being eggs and were quite inactive whilst undisturbed, 

 they were in reality larvae which, as soon as they were liberated, were 

 exceedingly active. They crawled about in the manner of J^si/rhe 

 larvse with their tails in the air (Fig. 4 a), bearing considerable 

 resemblance to a youngster walking on his hands with his heels in the 

 air. There must have been many hundreds in each case, and the 



