TETRAMEROUS PLANT-BEETLES. 171 



proportion of the iDJurious Chrysomelidse, such as the Striped cucum- 

 ber-beetle, and the various species of flea-beetles, so injurious to the 

 vine, the cucumber, and the Crnciferse, or plants of the cabbage and 

 turnip family ; and they furnish a remarkable exception to noxious in- 

 sects in general by being usually most injurious in the perfect or beetle 

 form. But some of them, like the Cucumber-beetle, (DiahroUca vittataj 

 also cause the death of the plants by burrowing into the roots in their 

 larva state. Some of the species, like the European Galeruca calmari- 

 ensis, and the little bronze flea-beetle, Haltica helxines, which is common 

 [Fig. 85.] to Europe and this country, depart from the usual 



habits of the family in devouring the foliage of trees, 

 .,-^j, whereas the great majority of Chrysomelidse feed * 

 I Jfc^ I upon herbaceous plants. The habits of the larvae 

 are various, those of Galeruca feeding exposed upon 

 jt. 2. the surface of leaves ; those of Diabrotica boring 



p5a?i'!TenlrahT'do7 i^^o roots, and those of Haltica sometimes feeding 

 sal view-after Kiiey. ^pQn poots, but usually mining between the laminae 

 of leaves. 



The sub-family is divided into two distinct groups: the Galerucini, 

 with the thighs not thickened, and the anterior coxae not separated by 

 the prosternam; and the Halticini, having the anterior coxae separated 

 by a projection of the sternum, and the hind thighs greatly enlarged, 

 which gives them the power of jumping, and from which the name of 

 fiea-heetles is derived The following are the principal genera : 



A. Hiud thighs not thickened. (Galerucini.) 

 B. Thorax wider than long ; first joint of antennae shorter than the second and third united ; color 



usually dull brownish, sometimes with black striijes Galeuuca. 



B B. Thorax almost square, wits rounded corners ; first joint of antennae as long as second and 



third united ; colors usually yellow and black combined Diabkotica. 



B B B. Thorax usually a little wider than long; second and third joints of antennae about equal ; 



size small ; color brown or metallic black, or blue, and without spots Lupekus. 



A A. Hind thighs enlarged for jumping. (Halticini.) 



C. Antennae distant, slightly thickened towards the tip; claws bifid Blephakiua. 



C C. Antennae approximate, filiform, claws simple or dentate. 

 D. Last joint of hind tarsi swollen. 



E. Elytra glabrous ; size about medium ; colors various CEdionychis. 



E E. Elytra hairy; size small; color brown Hypolampis. 



D D. Last joint of hind tarsi not inflated. 



F. Elytra irregularly and finely punctured; size medium or small. 

 G. Body oval ; thorax wider than long. 

 H. Thorax with an impressed transverse line before the base ; color blue-black : 



Gkaptodbea. 



H H. Thorax without impression. 



I. Tarsi of ordinary form. 



K. Second joint of antennae shorter than the third ; size medium ; colors various : 



DiSONYCHA. 



K K. Second and third joints of antennae equal; size small; color dark metallic; 

 elytra usually with one yellow stripe Orchestris. 



I I. First joint of hind tarsi as long as the others united , size very small ; color 



brownish LoNGiTARSUS. 



G G. Body elongate ; thorax about as long as wide; size small; color black, sometime.s 

 striped with yellow , Systena, 



