TETRAMEROITS PLANT-BEETLES. 171 



proportion of the injurious Chrysoinelidae, sudi as the Strijied cucum- 

 ber-beetle, and the various si)ecies of flea-beetles, so injurious to the 

 vine, the cucumber, and the Cruciferse, or plants of the cabbaf,'e and 

 turnip famih'; and they furnish a remarkable excei»tion 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, ( Diabrotica vittatuj 

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

 larva state. Some of the species, like the European Galcruca cahnari- 

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

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



habits of the family in devouring the foliage of trees, 

 ^ T ]t~^l T '^'^♦^^^'^s the great majority of Chrysomelidae feed 

 S I ifcsft 1 upon herbaceous plants. The habits of the larv* 

 are various, those of Galeruca feeding exj)osed u{)on 

 J. 2. the surface of leaves ; those of Diabrotica boiing. 



PiSrrTlmrai72!''do7 "'t<^ roots, and those of Ilaltica sometimes feeding 

 sal view-alter itiJey. upon roots, but usually miuiug between the lamiuie 

 of leaves. 



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

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

 the prosternum; and the Halticini, having the anterior coxa? 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 

 Jfea-bcetles is derived. The following are the principal genera : 



A. Him\ thighs not thickened. (Oalerucini.) 

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



nsually dull hrownish, sometimes with black stripes Gau.kica. 



B B. Thorax almo.st square, wim rounded corners ; tirst .joint of antenna aa long as second and 



tliird united ; colors usually yellow and black combined Dlabkotica. 



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



size small; color brown or metallic black, or blue, and without spots Ll'pekus. 



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



C. Ant«nn;b distant, slightly thickened towards the tip; claws bifid Blephakida. 



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

 D. Last joint of hind tarsi swollen. 



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



E E. Elytrahairy; si/.csmall; color brown HvpOLAiiPls. 



D D. Last joint of hind tarsi not intiated. 



F. Elytra irregularly and tinely ]>unctured ; eize medium or small. 

 G. Body oval ; thorax wider than long. 

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



GHAn^ODERA. 



H H. Thorax without impression. 



I. Tarsi of ordinary form. 



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



DiSONYCHA. 



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

 elytra usually with one yellow stripe ORniEsTRW. 



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



brownish Lonc;ita r.sl's. 



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

 striped with yellow StbteXA. 



