212 BRITISH BEETLES. 



lidae, Chrysomelidce, Gallerucida, Halticidte, and Cassi- 



The SAGRID^; (which comprise some very large and 

 splendid exotic insects) are here only represented by a 

 single genus, Orsodacna; the few British species of which 

 are of considerable rarity, being usually found in the 

 blossoms of the whitethorn. They are small, narrow, 

 linear insects, exhibiting no particular points for obser- 

 vation. 



In this family the apex of the mandibles is entire, 

 without emargination ; and the labium is deeply incised, 

 so as to become bilobed. 



The DONACIAD^E have the antennae long, and inserted 

 before the eyes; the head prominent, and rather con- 

 stricted behind; the first segment of the abdomen as 

 long as all the rest together; and the legs long and 

 straggling, the femora (and especially the hinder pair) 

 being often much thickened and toothed on the under 

 side. 



We possess two genera, Donacia and Hcsmonia ; th 

 members of which are exclusively attached to water- 

 plants (as the specific names of many of them import), 

 in the stems of which their naked larvae are found ; the 

 pupae being enclosed in transparent silken cocoons, at- 

 tached to the roots or filaments. The Donaciae are all 

 more or less coarsely punctured and metallic above, with 

 fine silky down on the under-side; they have a narrow 

 thorax and somewhat flattened elytra, and are usually 

 found in great numbers, being gregarious. Some of the 

 species have a variegated longitudinal metallic stripe on 

 each wing-case ; and a few are exceedingly variable in 

 colour, specimens of all shades from dull black to light 

 brass being seen together, the intermediate examples 



