1186 



FAMILY Lttl. CHRYSOMELID.E. 



LII. Disonycha Cliev. 1834. (Gi\, "two + claw.") 



Oblong or oval beetles of medium size, having the head inserted 

 as far as the eyes, front with distinct carina and two tubercles; 



antenna? slender, rarely 

 longer than half the 

 body, the fourth joint 

 longer than third, ex- 

 cept in the species with 

 blue elytra, where the 

 two joints are equal ; 

 thorax as wide at base as 

 elytra , narrowed in 

 front, sides obliquely 

 sinuate, disk convex 

 without transverse basal 

 depression; elytra ob- 

 long or oval, the epi- 

 pleur^e gradually nar- 

 rower from base ; front 

 coxal cavities open be- 

 hind ; hind thighs much 

 enlarged, grooved be- 

 neath ; tibia? more or less 

 bisulcate on outer face, 

 terminated by a moder- 



Fig. 521. Disonycha irimgidaris jSay. X 10. (After Forbes.) j i'&tG Spur ; first joint of 



hind tarsi as long as the next two ; claws dilated at base. The males 

 have the last ventral segment truncate, the pygidium vertical and 

 convex ; in the females the last ventral is oval and the pygidium 

 horizontal. 



The species feed upon herbs of various kinds and often do much 

 damage to sugar beets and allied plants. They feign death when 

 disturbed, falling to the ground, where they remain quiet for sev- 

 eral minutes. Of the 18 species ascribed to the genus by Horn, 

 eleven have been taken in the State. 



KEY TO INDIANA SPECIES OF DISONYCHA. 



a. Form elongate, parallel; elytra yellow with black stripes, subsulcate on 

 the sides: thorax with an irregular impression each side. 



2191. PEN NS YLVANICA. 



aa. Form more or less oval: elytra not subsulcate; thorax regularly con- 

 vex. 



1). Elytra with black and yellow stripes, or yellow with only a narrow 

 sutural and suhmarginal black line. 



