THE WATER-BOATMEN. 



1063 



anchoring themselves to some submerged object while feeding 

 and the fringed hind ones for swimming or for cleaning the 

 body of accumulated ooze. Both adults and nymphs gather 

 their food supply from ooze at the bottom of the pool which 

 they inhabit. It consists mainly of remnants of aquatic plants, 

 such as Spwogyra, Zygnema, etc., together with such minute 

 forms of animal life as they may at the same time gather in. 

 More than 150 species of the family are known, distributed in 

 all countries of the world. In Mexico and Egypt certain species 

 are used as food by the natives and others are collected and sold 

 in quantities for the food of cage birds. Of their habits Uhler 

 (1884, 251) says: 



Fig. 215. Structures of Corixid.;e. 

 a. Adult of Arcticorixa alternata (Say), X 6 ; b, pala of male of A. obliqua Hung. ; 

 c, pala of male of Rainplioron.rn acuminata (Uhl.) ; d and c, heads of male and fe- 

 male of same species from above; /, ventral view of male abdomen of A. alternata, 

 showing the peculiar asymmetry of the terminal segments ; g, same of female, show- 

 ing regularity of segments ; h, side view of head and front legs of a Corixid, illus- 

 trating the process of food gathering, one fore leg with stylets exserted passing food 

 material across the face and over the mouth opening, the other stretched out in the 

 act of gathering material ; i, adult male of Palmacori.ro buenoi Abb. ; j, pala of male 

 of P. fiillettl Abb. ; k, pala of male of A. gordita Abb. ; /, pala of male of Corixa 

 macroceps Kirk. (After Hungerford and Abbott). 



"These insects are truly aquatic, but they occasionally leave the wa- 

 ter and during their nocturnal nights are drawn to the lights in our 

 houses, into which they dash with headlong precipitation. They live on 

 the bottom in puddles, ponds and running waters and where there is no 

 current may be seen balanced with the neatest delicacy by the tips of 

 their intermediate feet, stationed in the midst of their young at intervals 

 of a few inches; then, by reason of some disturbance, dashing away with 

 rapid strokes of the posterior paddles. When they arise to the surface 

 to take in a fresh supply of air they rest horizontally for an instant with 

 the long middle legs extended forward and the sides and ventral margin 

 become glazed with an air-film which shines like translucent silver." 



Abbott (1923, 386) says: "They swim through the water, 

 back uppermost, in irregular rapid jerks and as a rule spend 

 the greater part of the time near the bottom clinging to sticks 



