DISTRIBUTE INSECT VARIETY. 299 



rust colour^ and the varieties take one or the other tint. The 

 larvae of Philbalapteryx lignata are yellowish green, more or less 

 suffused with pink, and those of the small Pi/rausta pimicealis 

 often want the darker stripes and lines. Sometimes, however, it 

 would appear that variation in the caterpillar state coincides with 

 aberration in the imago, since Merope, an Alpine variety of our 

 Marsh Fritillary butterfly, according' to Boisduval, has a special 

 larval form with yellow dorsal spots, resembling that of Cynthia. 

 Caterpillars and other phytophagous larvae, as well as amor- 

 phous and exposed pupae, have been noticed to vary according to 

 their aliments and the season, as also, chameleon-like, to assume 

 the colour of the objects on which they rest ; and in the case of 

 the two grey moths Acronycta tridens and psi, we have a reputed 

 instance of dissimilar hump-backed caterpillars, the one orange red 

 and the other yellowish black, producing perfect insects that can 

 be discriminated by no specific characters, and in the case of the 

 Chalk Hill Blues very similar larvae produce distinct imagines. 

 As regards variation of pupae when exposed, the chrysalis of the 

 Swallow Tail [Papilio podalirius) is in Italy reddish in autumn, 

 green or brownish in the spring, and that of the indigenous 

 Machaon varies in colour with the object on which it is placed. 

 The pupa of a South African butterfly [Anthrocharis Keiskamma) , 

 according to Mr. T. P. M. Weale, varies from greenish- white to 

 bright green, ochreous, and brown, according to the substance to 

 which it is attached, being lightest on a blue surface exposed to 

 light, and darkest on brown leaves in obscurity. The pupa of 

 another species on a white surface became so pale-coloured as to 

 be almost translucent, with the marking on the ventral aspect of 

 the abdomen almost obliterated. The larvae of the Acraa Erehia 

 of Hewitson confined in a dark box produced darker pupae. The 

 caterpillar of our Peppered Geometer is likewise stated to be 

 yellow when it feeds on birch, yellow or brown when it feeds on 

 elm ; that of the Death's Head Hawk has two varieties. In 

 certain cases larvae have also been found to vary indifferently as 

 regards their armature of spines and hair, if not as regards their 

 actual forms. So that when, on the other hand, we discover a 

 majority of leaf -feeding larvae and pupae protected by mimicry to 

 the leaves, twigs, and stems of plants on which they feed, and 

 that those feeding exposed are distasteful to insectivorous creatures. 



