THE LEAF BEETLES. 



L099 



They have the head prominent, somewhal nan-owed behind tin; 

 eyes ; antennae filiform, slender, at Least half as Long as body ; 1 horax 

 quadrate without side margins, not wider than head. Elytra wider 

 than thorax, depressed, cylindrical or somewhat triangular, usually 

 narrowed toward the tips/and each marked with ten rows of quad- 

 rate, rarely rounded, punctures. In color .they are usually more 

 or less metallic, of a greenish, bronze or purplish hue. The under 

 side is paler and densely clothed with a fine silky pubescence, which 

 enables them to shed the water when the plants upon which they 

 alight happen to be submerged. 



The principal papers treating of the tribe are as follows : 

 LeConte. — "Synopsis of the Species of Donatio, Inhabiting the 

 United States," in Proc. Phil. Acad. Nat. Scl, V, 1851, 

 310-316. 



Leng, Chas. — "Review^ of the Donatio of Boreal America," in 



Trans. Amer. Ent. Soc, XVIII, 1891, 159-176. 

 The tribe comprises but two genera, both of which are repre- 

 sented in Indiana. 



KEY TO GENERA OF DONACIINI. 



a. Elytra simple at tip ; tarsi dilated, spongy beneath. I. Donacia. 



aa. Elytra distinctly spinose at tip; tarsi narrow, smooth beneath, last joint 

 very long, claws large. II. H.emonia. 



I. Donacia Fab. 1775. ' (Gr., "a reed.") 



Belonging to this genus, as characterized above, Leng, in his 

 latest synopsis, recognized 20 species and a number of varieties. 

 Eighteen species have been taken in Indiana, while four others may 

 occur. 



In those species having the "suturai margin sinuate behind the 

 middle," there is an apparent second margin, starting not more 

 than one-fourth the length from the tip — often less — which is sinu- 

 ate, or curved more or less, away from the suture. Thus a space 

 somewhat elliptical in shape is formed, sometimes depressed, some- 

 times in the same plane with the rest of the elytron, and always 

 destitute of punctuation. 



The males are narrower than the females and usually have the 

 hind femora more strongly toothed and the last dorsal segment 

 shorter and either truncate or emarginate, never rounded. Last 

 dorsal of female more or less elongate, always rounded. For con- 

 venience the Indiana species are separated into three groups and 

 these in turn into species. 



