406 



THE HYDROCORES, 



considered as the natural position with his back up- 

 wards, the former reverses this arrangement and 

 swims with his back downwards. In the structure of 

 the body we find the same peculiarities which are 

 generally met with in active aquatic insects: the 

 body, although rather elongated, is compact, and 

 thickest before the middle, the head is broad and 

 rounded, and there are no projections which can 

 hinder its progress through the water. 



The Notonecta glauca measures about three-fifths 

 of an inch in length, and its general colour is yellow, 

 smooth and shining on the head and prothorax, but 

 dull and somewhat glaucous on the hemelytra. The 

 scutellum is black, the eyes dark brown, and the 

 lower surface of the body blackish. It varies a good 

 deal, however, in the colouring of the hemelytra; in 

 the ordinary specimens the outer margins of these 

 are spotted with black, whilst other individuals have 

 the corium reddish, marbled with black, and others 

 again have nearly the whole of this part black, with 

 the exception of two broad yellow dashes at the base. 

 The body is very convex or almost ridged above, so 

 that the membranes of the hemelytra, in folding over 

 each other, lap round the body as it were, and the 

 wings, which are protected by them from the water, 

 are of large size and very delicate texture. Upon 

 these the Notonectce, like the Water-beetles, are well 

 able to raise themselves in the air, and they, as well 

 as the other species of the tribe, appear to be fond of 

 quitting their native element. In their habits they 

 are exceedingly predaceous, their short, three-jointed 

 rostrum being as powerful an organ as that of the 

 Reduvius, referred to in a former page ; and it is said, 

 although my own experience does not confirm this, 



