58 BRITISH BUTTERFLIES. 



instar, but change their habits with the third moult; for they no 

 longer feed by day on the upperside of a leaf, but rest on the petiole 

 of a leaf head downwards, and feed only about sunrise and sunset, 

 and, when they feed, eat at the edge of a leaf, consuming stalks 

 and stipules of very young leaves. These habits are now continued 

 throughout life. When full-grown, the larva rests lengthwise, 

 with the thoracic segments slightly raised, and the head bent under, 

 the first pair of legs not resting on the stem. The larva is very 

 sluggish, only moving when compelled. If irritated, it does 

 not fall, but, if made to fall, it forms a complete ring, but soon unfolds 

 and climbs up a fresh stem. Frohawk adds (tint., xxvi., p. 185) that 

 the larva of C. edusa, after the third moult, resembles very closely the 

 colour of the upper surface of a clover-leaf, and rests with its 

 anterior segments slightly raised in a gentle curve, feeding during 

 the day in sunshine or shade, but preferring the former. These 

 detailed notes as to the feeding- and resting-habits of the larvae 

 of Colias edusa are largely applicable to those of most other 

 species of which the larvae are known. Thus Scudder observes 

 (Butts. New Engl., ii., p. 1120) that the young larva of Colias philodice 

 rests on the midrib of a leaf, usually upon the upper surface with 

 the head indifferently towards the base or apex of the leaf, and maintains 

 this position after the first moult and can scarcely be seen, so closely 

 does its colour resemble that of the leaf. He also notes that, when 

 first hatched, the larva makes a hole in a leaf, feeds at its edges for 

 several days, and then makes another, and so on until only the 

 principal veins are left. In its later stages, however, it devours a 

 leaf from end to end ; and, in this stage, rests upon the stalk of a 

 leaf, with the first two pairs of true legs raised from the surface and 

 extended forward. Edwards says that the young larvae of this species 

 tend to roll off the leaves, and retain this feature till they are mature, 

 so that it appears to be a means of protection against enemies. 

 Scudder says {op. cit., p. 1132) that the full-grown larva of C. 

 eurytlieuie moves forward in a series of scarcely perceptible starts. 

 Frohawk states (tint., xxv., p. 273) that, when the larva of Colias 

 hyale is quite } T oung it ieeds on the upper cuticle of a leaf, close to the 

 midrib, and, after each meal, returns to the midrib, along which it rests 

 in a straight position, with its head furthermost from the spot where 

 it feeds, and is very sluggish in its movements ; when a few days old 

 the larva eats through a leaf, completely perforating it, and generally 

 attacks a leaflet near the tip. Just before hybernation it rests in a 

 straight position, but, upon any disturbance, elevates the anterior 

 half of its body, remaining in a curved attitude for a few minutes 

 and then attains its former posture ; it feeds principally by day, and 

 prefers the sunshine. Williams observes (tint., xxvi., p. 8) that, in the 

 third skin, the larva of C. hyale corresponds exactly in colour with a 

 clover-leaf. The feeding- and resting-habits of the huvae of those species 

 that feed on Vaccinium are very similar. Lyman observes (Can. tint., 

 1897, pp. 219-258) that the larva; of Colias interior eat the parenchyma 

 of the Vaccinium leaves in small round patches, feeding on the upper- 

 side of the leaves, and resting, when not feeding, along the midrib, the 

 head sometimes up, and somet mes down. After hybernation, and 

 when the second moult is passed, they eat entire. leaves (when young 

 and tender). The larvae are decidedly sluggish for the greater part of the 



