﻿vim ARADIDAE — IIEBRIDAE — HYDROMETRIDAE 551 



breast, so that the rostrum is free. Of the five species, three 

 occur in Chili and Patagonia, two in Tasmania, and one in 

 Australia. 



Fam. 8. Hebridae. — Minute hugs, of semiaquatic habits, 

 clothed beneath with a dense, minute, silvery pubescence; antennae 

 five-jointed; legs of not more than average length ; elytra in larger 

 part menibranous.——Thia small family consists altogether of only 

 about a dozen species ; we have two species of the genus Hebrus 

 in Britain ; they are usually found in very wet moss. 



Fam. 9. Hydrometridae. — Form very diverse; antenna* 



four-jointed, tarsi two-jointed. Coxae usually widely separated. 



Either wingless or with elytra of one texture throughout, having 



no membranous port. Under surface with a minute velvet-like 



pubescence. In many forms the legs are of great length. — Although 



of comparatively small extent — scarcely 200 species being at 



present known — this family is of great 



interest from the habit possessed by its 



members of living on the surface of 



water. In the case of the notorious 



genus Halobates (Fig. 265) the Insects 



can even successfully defy the terrors 



of Xeptune and live on the ocean 



many hundreds of miles from land. 



There is great variety of form among 



Hydrometridae. The European and 



British genus Mesovelia is of short 



form, and but little dissimilar from 



ordinary land-bugs, with which, indeed, 



it is connected by means of the genus 



Hebrus, already noticed. Mesovelia 



represents the sub-family Mesoveliides, 



which, though consisting of onlv four 



species, occurs in both hemispheres, and 



ia the tropics as well as in the tern- _ 



m L , riG. 26o. — Halobates sobnmts. 



perate regions. Our species, M.furca ta, Under surface of a female 



walks on the surface of the water, the c ^ rv - - Pacific Ocean. 



Marques 

 movements of its legs and the posi- 

 tion of its coxae being those of land -bugs. Another British 

 Insect — the highly remarkable Hydrometra stagnorum — is of 

 excessively slender form, with long thin legs, by aid of which it 



