1096 



FAMILY LIIT. C HR YSO MELID JE . 



on the inner side, finely granulated ; mandibles usually short and ro- 

 bust, labrum transverse, usually rounded in front, Antennae varia- 

 ble in position and form, serrate or lamellate in certain Clythrini, 

 clavate in many Hispini, not inserted upon frontal prominences, 

 usually 11- jointed. Thorax often margined at the sides, the side 

 pieces not separate from the presternum, which is not prolonged. 

 Elytra usually covering the abdomen, sometimes leaving the last 

 dorsal segment exposed; rarely (in some Galerucini and Chrysome- 

 lini) smaller and not covering the greatly enlarged abdomen of fe- 

 male; abdomen with five ventral segments. Legs usually short, 

 hind thighs often enlarged for jumping • tibia? never serrate, usually 

 without spines; tarsi (except in Rcemonia) with joints one to three 

 broad and covered beneath with a brush of hair, fifth with two equal 

 claws of variable form. 



The name of the family is from that of the typical genus, Chrys- 

 omela, which is derived from two Greek words meaning ''gold" and 

 "fruit," and probably refers to some of the members of the genus 

 Cassida, which are often of a brilliant golden hue. They are called 

 leaf beetles because they feed upon the leaves of plants, the Colo- 

 rado potato beetle and striped cucumber beetle being familiar ex- 

 amples. All the species are diurnal in habit and move slowly over 

 the surface of plants, to which they adhere by means of the dense 

 brush of hairs upon the under side of the tarsi. "As the function 

 of the Cerambycidae is to hold the vegetable world in check by de- 

 stroying woody fiber, the Bruchidae effect a similar result by attack- 

 ing the seeds and the Chrysomelidae by destroying the leaves. As 

 the cellular and succulent-leaved plants have succeeded the drier 

 and more woody forms of early geological time, so have the Chrys- 

 omelidae probably attained their highest development in the more 

 recent periods."* 



On account of their leaf-eating habits the family comprises some 

 very injurious forms, which will be mentioned in their proper se- 

 quence. The eggs are usually yellowish and elongated and are gen- 

 erally laid upon the leaves or stems of the plants upon which the 

 larvae feed. The latter are of varying form, but for the most part 

 are fleshy convex or chunky hump-backed "slugs" or grubs, a 

 familiar example being that of the Colorado potato beetle. Many 

 of them live on the leaves of the plants, where they feed often in 

 company with the mature insects. Those that live exposed to the 

 light differ from the great majority of Coleopterous larvae in being 



*LeConte and Horn, Classification, p. 335. 



