

Lonaciina.} iTivTornA-.A. 



and the tarsal claws are large and strong and simple ; the undcr-sMi- <( 

 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 diluted aud strongly 



piitifscent beneath DONACIA, F. 



II. I'pper sin face not metallic; elytra produced into a strong 

 rpine at their external apical angle; tarsi with the three 



first joints narrow and not pubescent beneath H^MOSI*, Curt. 



DON AC! A, 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. tagittariae is figured by Chapuis and Candeze (Cat. des Larres 

 des Coleopteres, pi. ix. fig. 1) ; it is of a dull white colour, with the head, mouth 

 parts, aud 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 ami 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 triauiyul.tr hooks ; the antennae are very short, 

 4-jointed, and the legs are short and slender, and not or scarcely visible from above. 

 The eggs of the Uouacite are arranged in rows on the lower side of the leaves of 

 water plants (such as Scrophularia, Xymphaa, Fotamogeton, &c. ; when the young 

 larva' are hatched, they take up their abode in the stems of these plants, in which 

 they become full grown in four or five mouths ; 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 pu|ta calls for no particular remark, 

 and soon changes to the perfect insect, which, however, passes the winter in the 

 cocoon, aud does not leave it until May or June in the following year. 



Our British species may be distinguished as follows : 



1. Tibia; 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 uudcr-sidc. 



