158 HALF HOURS WITH INSECTS. [Packard. 



water beetles, so far as we have observed, secrete a similar 

 fluid, but in less abundance. 



Equally, if not more, perfect in its adaptability to aquatic 

 life is the Notonecta, which, as its name implies, swims on 

 its back. Now look at the form of the body. The back, 

 usually broad and flat in the Hemiptera, is here rounded like 

 the keel of a canoe, while the under side is flat, forming the 

 deck of the boat, to which the oars are attached by a set of 

 automatic row-locks. The head is bent over and submerged 

 in front ; the eyes are partly above and partly beneath the 

 water, so that a double outlook into two worlds is secured. 

 The antenuje are tucked away out of sight in a groove under 

 the eyes. The end of the body is pointed, affording no re- 

 sistance to the water, and 

 Fig. 126. ' 



the posterior half of the 

 body is fringed with long 

 spreading hairs, which aid 

 in buoying the body up. 

 The adjoining cut (12G) 

 gives an idea of the atti- 

 tude of the Notonecta 

 xotonecta. when at rest at the sur- 



face of the water, back downwards. The hind feet are 

 beautifully fringed, and while swimming it feathers its oars, 

 the hairs of the blade being pressed to the leg as it is drawn 

 forwards, and again spreading out with the backward stroke 

 of the limb. In this insect, as well as in Corixa, as Schiodte 

 observes, the hind legs are moved both together, as in Dytis- 

 cus. In Belostoma, and probably Ranatra, they are moved 

 alternately. When about to fly from its pool, which it does 

 by day as well as by night, as is the case with Corixa, it 

 dives a little way down, and then leaps suddenly straight up 

 out of the water, and spreads its wings, flying rapidly off. 

 All the water bugs and beetles are careful to keep them- 

 selves clean and smooth. Particularly necessary is it for 



30 



