582 INSECTS AT HOME. 



forwards. In fact, the movv^ment of the Water-boatman's leg 

 very much resembles that of the North American Indian's 

 paddle. He never takes the paddle out of the water, but lirst 

 makes his stroke with the flat of the blade, and then turns the 

 paddle so that its edge is presented to the water as it is 

 brought forward in readiness for the next stroke. 



One of these insects, Notonecta glauca, is shown on Plato 

 XIX. Fig. 2. 



The manners and customs of the Water-boatmen are well 

 worthy of study, and I have passed many pleasant hours in 

 watching their habits, both at liberty and in captivity. As a 

 rule, they lie on their backs in the water, but they do not 

 always maintain this position. On fine, hot, summer days, 

 they turn over and sit almost on the surface of the w\^ter, with 

 the wing-cases half open and the wings partly protruding from 

 them. In this curious attitude thev will sit for an hour at 

 a time, and even more unless disturbed, as long as the sun 

 shines on them. It is remarkable how mere attitude will 

 alter the aspect of an insect. The Water-boatman, as it 

 appears when darting through the water, and when sitting 

 sunning itself on the surface, is so totally different in aspect, 

 that no one who was not acquainted with the insect could 

 suspect its identity. 



As is tlie case with aquatic insects in general, the Water- 

 boatman breathes atmospheric air, respiration being conducted 

 much like that of the Water Beetles, which have already been 

 described. In the case of the Water-boatman, however, the 

 comparative transparency of the elytra enables the mode of 

 respiration to be seen better than can be done with the 

 beetles. I have often watched the breathing of the Notonecta, 

 which is conducted as follows. The insect lies on its back, 

 witli its legs spread, the tip of its tail just above the surface 

 of the water, and its head just below it. Air is taken into the 

 space between the elytra and the body, and is passed onwards 

 towards the shoulders, being alternately taken in and ejected 

 through the spiracles, and its course being traceable by the 

 quicksilvery look which it gives to the elytra. Having com- 

 pleted its course through the respiratory system, the air is 

 sqeezed out at the junction of the elytra with the under part 



