CHAPTER n. 



HYDROCORISA, OB WATER-BUGS. 



We now come to the second group of Heteroptera — the Hydro- 

 corisa, or Water-Bugs. There are many species, differing 

 greatly in external appearance ; but they all have very short 

 autennse concealed in cavities beneath the eyes, and their fore- 

 legs are rather short, and can be folded close to the body, so as 

 to look like claws. With these limbs the insects seize their 

 prey, which consists of various inhabitants of the water that do 

 not appear to be so strong as themselves. 



The first family is that of the Notonectidte, which embraces 

 the various insects known by the popular name of Water- 

 boatmen. The scientific name signifies Back-swimmer, and 

 both titles are equally appropriate. The Notonectidse have a 

 habit of lying on their backs in the water, and their body 

 then assumes a shape very much like that of a boat. The two 

 hind legs are exceedingly long, and as they are stretched out 

 at right angles with the body, look exactly like oars, and in- 

 deed are used as if they were oars. The ends of these legs are 

 furnished with hairy fringes, which act like the blade of the oar, 

 and enable the insect to drive itself along with very great speed. 



All who have handled an oar know of the difficulties which 

 beset them in the proper mode of feathering, i.e. turning the 

 oar as it is brought out of the water, so that the edge of the 

 blade is turned to the air as the oar is swept backwards for the 

 next stroke. In the oar-like legs of the Water-boatman we 

 find a provision for a similar feathering, the bristles standing 

 out boldly as the leg is forced against the water to make the 

 next stroke, and collapsing as the limb is drawn through the 

 water in readiness for the next stroke. The insect never lifts 

 its car-legs out of the water, and, unless some provision of the 

 sort were made, it would travel nearly as fast backwards as 



