THE COLORATION OF BUTTERFLY LARVAE. 61 



prothorax being directed exactly dorsal, and the legs of the meso- and 

 metathorax forwards. As the head is carried to either side, these 

 forward segments so rotate that the venter becomes ventral over all 

 segments, but the forward segments instead of being bent dorsally, are 

 bent laterally, and the head is against the side of the 2nd and 3rd 

 abdominal segments. In all these positions, the loop seems to be 

 fairly tense. When the head is bent to one side, the girth passes over 

 the middle of the 2nd abdominal segment and the middle of the 

 prothorax, the portion of the larva between these two positions being 

 in front of the loop, the rest behind it. In the median position there 

 is, perhaps, a large proportion of the prothorax in front of the loop ; 



indeed, the head only might be regarded as behind the loop 



The completion of the process, when the spinning is done, is really 

 very different from that in Papilio machaon. In the latter, the front 

 of the head is put forward under the loop, and it is slipped back into 

 its place by a movement very similar to that by which a thread is added 

 to the girth ; in Pieris rapae, at the end of fixing the last thread at the 

 side, the head is merely drawn forward from under the loop. Reference 

 might with advantage be here made to Riley's account of the spinning of 

 the girth by the larva of Euphoeades troilus, published by Scudder 

 (Butts. New England, pp. 1323-4). 



CHAPTER XIII. 



THE COLORATION OF BUTTERFLY LARVAE. 



Many eminent naturalists, including Lubbock and Weismann, 

 have pointed out that the larvae of lepidoptera are generally green in 

 their earliest stage. So far as the larvae of butterflies are concerned, 

 this is only very partially true, and it is well-known that the larvae of 

 the Papilionids, Vanessids, Argynnids, and other groups are rarely so. 

 On the other hand, the young larvae of the Urbicolines, Lycaenines, 

 Pierines, Satyrines, etc., are very generally so, especially in the case 

 of those species that live on low herbs. Scudder points out that, 

 among the American species, the young larva of Oeneis macouni is even 

 brilliantly striped, those of nearly all Papilionids are almost black 

 with a white saddle (as in the Palaearctic species), whilst many 

 others, e.g., Eurymus and Basilar chia, though having a green tinge, 

 are, nevertheless, so obscured by other colours, as to have a dusky 

 effect, which leaves the colour at most only greenish. We have only, 

 in our own limited fauna, to point to the larvae of Papilio machaon, 

 Aporia crataegi, Pieris brassicae, Aglais nrticae, Vanessa io, Melitaea 

 cinxia, etc., to show how little the suggestion is universally true, 

 whilst admitting, on the other hand, that the larvae of many butterflies 

 are, when newly hatched, nearly of the colour of the green leaves on 

 which they feed, the various changes in tint which we find in adult 

 larvae being assumed during growth. 



We have already pointed out (antea, pp. 18 et seq.) that the larvae of 

 most butterflies are, when hatched, of a generalised form with 

 exceedingly simple tubercular structure, and that, at the first or second 

 moult, great changes often take place. Scudder points out as being 



