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 lugs, of semiaquatic habits, 

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

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

 part membranous. This 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; antennae 

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

 Either wingless or with elytra of one texture throughout, having 

 no membranous part. 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 Neptune and live on the ocean 

 many hundi'eds 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 only four 

 species, occurs in both hemispheres, and 

 in the tropics as well as in the tern- 

 perate regions. Our species, M.furcata, 

 walks on the surface of the water, the 

 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 



Halobates sobrinus. 

 Under surface of a female 

 carrying eggs. Pacific Ocean 

 (Marquesas). 



