THE WATER-GNATS. 577 



Those specimens in which the wings are fully developed can 

 use them well. I have noticed that, when alighting in the 

 water after flight, they always use their legs for the purpose of 

 tucking the wings under the elytra, just as the earwig uses its for- 

 ceps and the rove-beetle the end of its flexible tail. With these 

 legs they wash themselves frequently, appearing to be singularly 

 fastidious respecting cleanliness. I have often seen these in- 

 sects standing on the three legs of one side, while employing 

 those of the other side in brushing the body, every portion 

 of which was carefully passed under the feet. The attitude is 

 most singular, and I have never seen it adopted by any other 

 insect. 



They are all predacious, seizing their prey with their fore-legs. 

 I have seen one of these creatures, having caught an insect, 

 hold it out in front of its body with its fore-feet, while making- 

 its way to some place where it could in safety suck the life- 

 juices of its prey. Predacious as they are, they also fall victims 

 to larger inhabitants of the water — the well-known Water- 

 boatman making great havoc among them, and taking on the 

 average five or six minutes in sucking dry the body of its prey. 



The name of the species shown at Fig. 1 is Hydrometra 

 gibhifera. Its colour is blackish-brown above, and beneath it 

 is black, with a silvery or brassy lustre when seen in a side- 

 light. The specific name of gibhifera, or bunch -bearing, is 

 given to it on account of a rounded tubercle or bunch upon 

 the anterior angles of the thorax. The male has also a large 

 orange -coloured tubercle on the back of the thorax, near its 

 junction with the abdomen. There is a short, thick, yellow 

 line drawn longitudinally on the middle of the front part of 

 the thorax. The elytra are blackish-brown, with a slight blue 

 gloss in certain lights, and the nervures are clothed with 

 golden hairs and scales. The middle pair of legs is the 

 longest. This species is very common on the surface of water, 

 whether it be stagnant or running. 



On Woodcut XLVIII. Fig. 2, is shown another species, 

 Hydrometra argentata. 



This insect is remarkable as being the smallest of the family. 

 Its colour is blackish-brown above, with a decided silvery gloss 

 below. The antennae are black. The colour of the elytra is 



p p 



