68 



CIIRYSOMELLtOE. 



(that is, having the two lobes joined), is absent*. The tibiae are 

 channelled on the outer edge ; the femora similarly channelled on 

 the underside for the reception of the tibiae. Anterior coxal 

 cavities open. Claws simple. 



Chrysomela differs from Chrysolina by having thementum small, 

 the episterna of the metathorax parallel, the lobes of the third 

 segment of the tarsi split ; the prothorax narrower than the 

 elytra, and the upper surface of the elytra confusedly punctate. 



Range. The species of the genus as a whole are recorded from 

 Europe and Asia, Tropical and South Africa, Madagascar, North 

 and Central America ; those of the subgenus Chrysomela, s. str.", 

 to which Ch. populi belongs, from Europe and Asia. 



Key to the Sp>ecies. 



Elytra bright red in the living insect, light 

 brown to red-brown in dried specimens, 



without metallic reflections Ch. populi, L., p. 68. 



Elytra metallic greenish, or occasionally viola- 

 ceous, with seneous reflections Ch. chlorina, sp.n.,p. 69. 



44. Chrysomela populi, L.f 



Chrysomela populi, L., Syst. Nat. ed. x, 1758, p. 370. 



Colour of elytra from light brown to red-brown, during life 

 bright red, of prothorax, scutellum and underside blue-black ; 

 sometimes the prothorax has a very slight greenish tinge; the 

 six thickened apical segments of the antennae piceous ; the 

 apices of the sutural margins of the elytra blackish, which is 

 sometimes obsolescent ; the colour of the underside varies, 

 sometimes being very light, almost brown. 



Head as broad as the emargination of the front edge of the 

 pronotum, deeply impressed with a Y-shaped mark on the upper 

 surface, which is closely punctate : areas round the roots of the 

 anteunae elevated and smooth. Antennae with the five basal 

 segments smooth and shining, the apical six covered with fine 

 pubescence ; first segment much thickened, second small, rounded, 

 third longer than fourth, fifth more or less globular and shorter 

 than fourth, the sixth to the eleventh gradually thicker. 

 Prothorax quadrate, broader than long, basal margin widely 

 arched, sides gradually rounded and slightly drawn forwards 

 at the anterior lateral angles ; the pronotum is gently convex 

 from side to side and finely punctate in its central area ; on 

 the lateral, elevated, longitudinal area, which is separated from 

 the central by a deep and oblique depression, the punctures are 

 much coarser. Scutellum triangular with apex rounded, and 

 surface smooth and impunctate. Elytra broader than the 

 prothorax; the surface of each is completely and closely covered 



* See footnote on p. 4. 



t For full bibliography, systematic, anatomical, and biological, see Weise, 

 Col. Cat., part 68, 1916, pp. 144, 145. 



