TETRAMEROTTS PLANT-BEETLES. 163 



which I have found of much use in preparing the following tables of 

 genera. Mr. Crotch unites all the Phytophaga in the family of Chry- 

 somelidir, which he divides into ten sub-families, as follows : Donaciides, 

 Orsodacnides, Criocerides, Melolonthides, Cryptocephalides, Chrysome- 

 lides, Eumolpides, (lalerucides, Ilispides and Cassidides. 



The Orsodacnides do not seem to us to be sufficiently distinct from 

 the Criocerides, nor the Melolonthides (questionably so called) from the 

 (vrytocephalides, nor the Eumolpides from the Chrysomelides, to be re- 

 tained as of equal rank. We will therefore divide the Chrysomelidie 

 into the seven following sub-families. The accompanying tables of the 

 minor groups exhibit a pretty full synopsis of N. American genera, ex- 

 cepting a few which are composed of but one or two rare species, usually 

 from the remote West : 



A. Body elongated; thorax not margined at the sides; liead slightly' constricted be- 

 hind the ej-es; eyes prominent; thighs usually more or less tliickencd. 

 IJ. Body much elongated; first ventral segment very long; larvte live in the stems 



of plants Donaciides. 



B B. Body moderately elongated ; first ventral segment not much longer than the 

 others ; larvaj live on the leaves of plants, sometimes cover themselves with 



excrement 1 CniocERiDKS. 



A A. Body more or less rounded (except Hispides) ; thorax almost always margined ; 



head not constricted ; e3-es not prominent; thighs not swollen (except iu 



Haltica and its sub-genera.) 



C. AntenuiB distant, being wider apart at base than the length of the tirst joint. 



D. Body oval; abdomen wholly covered by elytra; larvae live exposed on 



leaves Curysomelldes. 



D D. Body usuallj^ short and sub-cylindrical; tip of abdomen vertical and 



uncovered; larviB live on leaves, iu portable cases. Cr^ttocepii.m.ides. 



C C. Antennji; approximate, being rarely wider apart than the length of the tirst 



joint. 



E. Antennte filiform and at least half as long as the body ; hind thighs, iu 



one division, enlarged for jumping; larvit live on leaves or between 



their laminse Galerucides. 



E E. Autennie less than half as long as the body, and more or less thickened 

 towards the tip. 

 F. Head exposed; form oblong and usually sub-quadrate; surface usually 

 strongly pitted or reticulated; larvie live between the laminae of 



leaves Hispides. 



F F. Head concealed under the thorax ; form hemispherical ; surface 

 usually smootii ; larvie live on leaves, covered by excrement : 



Cassidide-s. 



Subfamily DONACIIDES. 



This sub-family, composed mostly of the geuus Dotuuin, Fab., forma 

 a couueetiug link between the Leptnrides of the preceding family and 

 the Criocerides of the pr<^.sent. Their form is considerably elongated, 

 and they can be distinguished with certainty by the unusual prolonga- 



