CHRYSOMELIDAE. 351 



Group III.— CEdionyches. 



Several species of (Edionychis, more imiiierous in the southern 

 part of the Atlantic region, represent this group in our fauna. 

 iSoiiie of them vary greatly in color, so that the limits of the 

 species are not well defined. 



Group IV. — Disonychas. 



These species arc of moderately large size, equal to ffidiony- 

 chis, and are prettily colored, frequently with striped elytra. They 

 differ from the Halticie (with which they have been associated 

 by Chapuis) by the prothorax having no transverse impression, 

 and from the Aphthona? by the shorter hind tarsi and greater 

 size. The prothorax has the basal margin oblique each side, 

 and sinuate at the middle ; the front coxal cavities are open 

 behind; the tibiae not deeply sulcate on the outer margin, the 

 spur of the hind pair is distinct but not large; the claws are 

 broader at base, but scarcely toothed or appendiculate. Th<^ 

 antenna? are moderately distant at base. 



The genus Disonycha is widely diffused, though feebly repre- 

 sented in the Pacific region. The species vary greatly in color. 



Group V. — Halticae. 



This group is represented in every part of the country by 

 species which, with the exception of H. rvfa, arc of a steel-blue 

 or bronzed color, easily known by the transverse impression near 

 the base of the prothorax, which is not limited each side by a 

 longitudinal plica. The antenna? are moderately distant at base; 

 the hind angles of the prothorax not obliquely rounded, nor tlu! 

 base sinuate; the front coxal cavities open behind; the tibise 

 feebly sulcate on outer margin ; 1st joint of hind tarsi as long as 

 the two following; claws appendiculate. The genus is commonly 

 known as Graptodera. 



Group VI. — Lacticae. 



Two species of Lactica in the Southern States represent this 

 group. They have the appearance of ffidionychis, but are known 

 by the very deep prothoracic impression, limited each side by a 

 basal plica. The other characters are those of the preceding 

 group. 



