58 LINKT-AN SYSTEM. 



qucntly the appearance of the most highly poUslicd gold or copper: 



the larva; live in wood. 



Sp. \. Bnpr. biguttatu. Crccn above, blue-green beneath; scutellum 

 transversely impressed; apex of the elytra serrated; a white villose 

 spot on each side of the sutmc, and three on the sides of the ab- 

 domen. 



In England it is rather rare, but was once observed in very great 

 abundance, by Dr. Latham, in Daren t-wood, Kent. 



Genus 31. IlYnuoi'iuLus, Fabr. Dvtiscus, Linn. 

 ^ntozM^ clavated, (■/«/> perfoliate: pa/pi fouv, fdiform: hinder feet cili- 

 ated and formed for swinnninir, w ilh minute claws. 

 The insects of this genus live in water and moist places. They 

 may be seen in ponds during the summer and calm mild days in 

 winter, frequently rising to the surface for fresh air; they swim well, 

 and when laid on their backs restore themselves by whirling round ; 

 they rest in the shade, keep in the water during the day, come abroad 

 in the evening, and are sometimes found sitting on the plants by the 

 edge; they fly by night; after having been long out of the water they 

 cannot dive but with difficulty: the foremost f(;et of the males have a 

 hemispherical appendage. The larvie always li\e in the water, and are 

 the crocodiles of their class, killing not only aquatic insects but even 

 fishes. 

 Sp. 1. Ili/droph. pkciis. Black; the sternum channelled and spiny 



behind. 

 Hydrous piceus. Leach, Jrom the Linnean MSS. 



This is the largest }>ritish species of the genus. The larva lives in 

 still waters and ponds; is about an inch and a half in length; black; its 

 head smooth and chesnut-coloured; with six short slender feet, which 

 arc actually placed on the bark, and a tapering tail through which it 

 respires. — In the month of July it is said to attain its utmost size, and 

 leaving the water, creeps upon the dry ground to a heap of dung, (cow- 

 dung if it be near,) and makes a hole under it pretty deep, and so wide 

 that it can lie in it rolled up in a circle, and Uiere it changes into its 

 pupa state. About the middle of August the perfect insect appears. 

 Like most of the aquatic insects it lives thr(jugh the winter, diving deep 

 into the mud in the most inclement weather. 

 Sp. 2. Hi/droph.caraboides. {PL 3. fig. 16.) 



Genus 32. Dvtiscus. 

 AntenntE setaceous ; palpi six, filiform : hind feet villous, formed for 

 swimming, with the claws very minute. (PL S.fg. 13, 14 Sf 1.5.) 

 The insects of tliis genus are very rmmerous, and are well deserving 

 the attention of the entomologist. In Dr. Leach's system they are di- 

 vided into several very natural genera : they are found in almost every 



