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 antennae 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 
the posterior half of the 
body is fringed with long 
spreading hairs, which aid 
in buoying the body up. 
The adjoining cut (126) 
gives an idea of the atti¬ 
tude of the Notonecta 
Notonecta. 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 Scliiodte 
observes, the hind legs are moved both together, as in Dytis- 
cus. In Belostoma, and probably Ranatra, the}* are moved 
alternately. When about to fty 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. 
Ail the water bugs and beetles are careful to keep them¬ 
selves clean and smooth. Particularly necessary is it for 
30 
