THE SILK-SPINNING HABIT IN BUTTERFLY LARVjE. 53 



the leaf; when this becomes too small, it makes a similar nest from 

 another leaf, but goes outside to feed on neighbouring leaves, generally 

 towards evening. 



The tiny larvae of Aporia crataegi, spin a web over two or three 

 leaves of their foodplant, within which they hide, coming out only to 

 feed, and extending their web as they increase in size. A specially 

 tough retreat is built for a hybernaculum, and, in this, a whole 

 community winters in safety. Our other Pierid larvae spin threads of 

 silk on which to walk, but, otherwise, none of the allies of A. crataegi, 

 in Europe, spin similar webs. Scudder, however, notes that a 

 Mexican Pierid constructs a web nearly as close as parchment. 



Belonging to an entirely different group of butterflies, but having 

 almost exactly the same gregarious habit as Aporia crataegi, the larvae 

 of Melitaea aurinia spin a silken tent over the young leaves of scabious, 

 in which they live, feeding only on the undersides of the leaves ; they 

 feed very slowly, and are still exceedingly small when they make their 

 hybernaculum, after leaving which, in the spring, they appear to live 

 singly and fully exposed, making, however, a silken cocoon by drawing 

 together several culms of grass, when fullfed, in which they pupate. 

 The larvae of M. aurinia are said to leave their hybernacula very 

 regularly, about March 1st in Co. Cork, in Ireland, although, in the early 

 season of 1893, they had already done so in mid-February. The larvae 

 of M. cinxia similarly pass their early lives and the winter gregariously 

 in a tent formed by a compact web, leaving its shelter in the spring for 

 another slighter structure. The hybernating web is larger than that under 

 which they feed, and is woven of silk, with grass and plantain stems inter- 

 mixed, and is well-roofed, so that the inner grass is quite dry. Luff says 

 that, in Guernsey, he had noticed the very young larvae of M. cinxia 

 on the webs, spun on their foodplant, in August and September, but that, 

 when he searched for their hybernacula in December and January, 

 in the same spot, he could not find them until he came accidentally 

 across a winter-nest whilst searching for beetles ; this was in the 

 centre of a tuft of grass, close to the roots ; it was pear-shaped, and, 

 with the larvae of M. cinxia were a number of larvae of Anthrocera trifolii, 

 hybernating with them. Luff says that they spin another web in spring 

 on their foodplant, but this is less compact than the winter-nest, although 

 larger. Most of the larvae leave the nest and live singly, when nearly 

 fullgrown, others, however, live more or less gregariously, even up to 

 the time of pupation. This mode of life is evidently not confined to 

 the Melitaeids of the Old World, "for Scudder notes a similar habit in 

 some of the Melitaeids [Cinclidia, Euphydryas, etc.) of North America, 

 which, living in company, cover at first a few leaves, then the whole head 

 of the plant, and eventually, sometimes, the whole plant, in a tolerably 

 firm web, within which the company feed, until the whole becomes a 

 nasty mess of half-eaten and dying leaves, and all sorts of frass, 

 including their own excrement and cast-off pellicles, everywhere 

 tangled with web. Within such a nest they hybernate, but not until 

 they have strengthened it with denser web, and drawn the leaves of the 

 head more tightly, so that it becomes a mere bunch which one may 

 cover with his hand, and which contracts the more apparently as 

 winter approaches. In the spring, they evidently have had enough of 

 this sort of communal life, and live, thereafter, in the open air." He 

 further notes that, whilst the larvae of Euphydryas phaeton hybernate 



