PACKARD.] INSECTS OF THE POND AND STEEAM. 159 



the Notonocta to keep its keel smooth, and it may often be 

 seen brusliing its back with its hind legs, or wliere the}^ will 

 not suffice, using the middle and front legs for this purpose. 

 It la3's its long, cylindrical eggs on the stems and leaves of 

 plants. The 3'oung hatch in about fifteen da^^s, appearing 

 in spring. The}' differ from their parent chiefly in wanting 

 wings. 



Corixa is in its form more like the slow moving punt, 

 being rounded nearly alike at both ends. The head is still 

 more bent and prolonged beneath, partly overlapping the 

 thorax. Its beak is minute and hidden from sight. 



So much for the swimming insects, of which we have men- 

 tioned the principal forms. There are a few of what may be 

 called sJcaters. They move like the AYherryman, or Gerris, 

 on the surface of the water, their feet being so constructed 

 as to enable them to run upon the surface without wetting 

 them. The middle pair of feet are longer than the hinder, 

 and they mostly perform the work of skating, being covered 

 with fine hairs which repel the water ; and thus the insect 

 skims over the surface with great rapidity, making very 

 short twists and turns like a practised skater. The under 

 side of the body is covered with short hairs like plush, form- 

 ing a repellent surface to the water. 



The fore limbs are much shorter and used at times in re- 

 taining their prey. Some of these Whcrrymen will be found 

 minus the hind wings, and are condemned to a life of com- 

 parative seclusion ; though it is said that the winged indi- 

 viduals seldom take flight. 



Far out in mid ocean in the tropics are found the oceanic 

 water-skaters, the Ilylobatos. Their fore legs are short, 

 outstretched, with thickened thighs. They are also wing- 

 less, the wing-covers alone being present. They course over 

 the surface of tiie ocean in large swarms, and are seen from 

 vessels many hundred miles from land. They are the true 

 "toilers of the sea" among insects. 



31 



