Donaciina.] PHYTOPHAGA. 267 
and the tarsal claws are large and strong and simple ; the under-side of 
the body is clothed with very thick silvery pubescence which repels 
water; the two genera may be distinguished as follows : — 
I. Upper surface metallic; elytra not produced into a spine at 
apex; tarsi with the three first joints dilated and strongly 
pubescent beneathy mp acl ec ic ant ne es eel eeen  DONACTARN ER. 
Il. Upper surface not metallic; elytra produced into a strong 
spine at their external apical angle; tarsi with the three 
first joints narrow and not pubescent beneath. . . . . . Hammonta, Curt. 
DONACIA, Fabricius. 
This genus contains about ninety species, which are chiefly found in 
Europe, Northern Asia, and North America; a few, however, have been 
described from India, Java, Cuba, &c. ; there are thirty European species, 
of which nineteen are found in Britain; they may be easily known by 
their brilliant metallic appearance and silvery under surface ; the upper 
surface is often variegated with brilliant red and purple markings ; they 
are gregarious in their habits, and are found on the leaves and stems of 
various water plants. 
The larva of D. sagittarie is figured by Chapuis and Candéze (Cat. des Larves 
des Coléoptéres, pl. ix. fig. 1); it is of a dull white colour, with the head, mouth 
parts, and prothoracic scutum yellow ; the form is subcylindrical, narrower in front, 
and widened very gradually behind, the greatest breadth being at about the fifth 
abdominal segment; the head is very small and retractile, with five ocelli on each 
side; the prothorax is longer but narrower than the mesothorax, and is armed with 
a somewhat corneous scutum ; the abdominal segments are eight in number, and are 
each divided on their upper surface into two parts by a transverse furrow, each 
part being furnished with a broad band of hairs directed backwards; the eighth 
segment is almost completely sunk in the seventh, and is furnished near its apex on 
the upper side with two ferruginous triangular hooks; the antennz are very short, 
4-jointed, and the legs are short and slender, and not or scarcely visible from above. 
The eggs of the Donaciz are arranged in rows on the lower side of the leaves of 
water plants (such as Scrophuiaria, Nymphea, Potamogeton, &e.; when the young 
larvee are hatched, they take np their abode in the stems of these plants, in which 
they become full grown in four or five months; in autumn they go down to the 
roots, and there form an oval cocoon which they attach to one side of the roots or 
filaments, forming knots along the stems; the pupa calls for no particular remark, 
and soon changes to the perfect insect, which, however, passes the winter in the 
cocoon, and does not leave it until May or June in the following year. 
Our British species may be distinguished as follows :— 
I. Tibie not produced externally into a tooth at 
apex; apex of mandibles only slightly projecting 
beyond labrum ; first segment of abdomen longer 
than the rest taken together (Donacia, i. sp.). 
i, Thorax and elytra without pubescence. 
1. Posterior femora of male armed with two teeth 
on their under-side, 
