INTRODUCTION. 



5 



(bearing the claws) arising from the base of the third. The 

 form of the claws in this subfamily is of taxonomic value ; they 

 may be simple or " appendiculate," i.e. angularly dilated on 

 the underside at the base, or split or cut in the middle (h'g. 30, 

 p. 80). Abdomen with five visible ventral segments, which may 

 be punctate or impunctate, glabrous or hairy ; male copulatory 

 armature, or cvdeagus, not (so far as is known) varying greatly 

 within this group. 



Larvce and Notes on the Life-history. 

 The larva? of Cmrysomelin^e feed on the foliage of plants, on 

 which they live more or less openly. They are of short, oval 

 or nearly oval form, very convex above, with short legs, and in 



Fig. 4. — Chrysolina exanthematica, Wied. : — la., labruni ; md., mandible; 

 ?nx., maxilla; L, labium. 



many species are brightty coloured. There may be one or several 

 generations in the year, the number of generations sometimes 

 varying in a single species in different parts of its range.* 



* [A paper by H. W. Dobson, ' Entomologist,' lvii, July 1924, pp. 159-163, 

 indicates that in certain species the lite-cycle may occupy two years, at least 

 in some parts of their range. Dobson observed the habits of Chrysomela 

 fashtosa in captivity. This species feeds on the Labiate Galeopsis tetrahit, 

 and he obtained from it a number of larvce in N.W. England in August 1921. 

 The majority of these larvae had become imagines by Oct. 1921, though a few- 

 individuals remained in the larval state through the winter. The adults 

 hibernated, emerging from their winter quarters early in 1922, and continuing 

 active through the summer of that year; many pairings were observed 

 between May and late August, but no eggs were laid. In the autumn of 

 1922 the adults again went into hibernation, and again emerged (except a fgw 

 which had died) early in 1923, when pairings took place from March till the 

 end of June ; eggs were at length laid later in the summer of 1923, and in 

 mid-August a number of larvre were feeding, just two years from the time when 

 those of the preceding generation were found. From Dobson's observations 

 it would appear that the same cycle was followed in a wild state, though 

 the times of emergence from winter quarters were on the whole somewhat 

 later. — Eds.] 



