AQUATIC INSECTS OF FRESHWATER 



FIG. 205. Shore-bug, Salda 

 signoretti. Enlarged. 



Streams and marshes. The toad-like appearance, the short and broad 

 body, mottled color and protruding eyes led to the popular designation. 

 They are ^ to % inch long, are all predaceous and live principally on 

 spawn, insect larvs and small snails. The most generally distributed 

 species of the United States are Galgulus oculatus, Pelogonus americanus. 

 Fig. 204, and Mononyx stygicus. 



Shore-Bugs belong to the family of Saldidse, 

 of which twelve species inhabit the United States, 

 four on the Atlantic Coast. They may often 

 be seen in considerable numbers on the margins 

 of water ways and take flight when disturbed but 

 soon alight. Their color is dark grey with white 

 and yellow markings, and their size ^ to 3/^ inch 

 in length. The most generally distributed 

 Eastern United States species are Salda signoretii, 

 Fig. 205, S. pellita, S. splacelata and S. anthracina. 

 Broad-Shouldered Water-Striders be- 

 long to the family of Veliidse and are distinct 

 and different from the true Water-striders. They are smaller, much 

 broader across the thorax and thicker of limb, all of them aquatic in habit 



and almost constantly on 

 the water, congregating 

 in school of hundreds. 

 The most generally 

 distributed species of the 

 Atlantic Coast States are 

 Hebrus americanus. Fig. 

 206, and Rhagovelia col- 

 laris. Fig. 207, both of 

 small size. All are pre- 

 daceous and feed on the juices of insects which fall into the water, mos- 

 quito larvse and the tiny alevins of fishes, when they come to the surface 

 of the water to take air. 



Water-striders belong to the family of Hydrometrid^e, slender 

 long-legged insects which dart about on the surface of ponds and pools 

 of both fresh and salt water. Some species are winged and others wingless, 

 varying in length from J^ to ^ inch. The elongated body has very 

 closely folded wings and long hairlike legs, both covered with minute 

 hairs, which prevent the insect from becoming wet and sustain it upon 

 the surface of the water, the legs being almost continuously lifted to 

 prevent their becoming wet, in which case the insect would sink into the 



FIG. 206. Broad-shouldered 

 Water-strider, Hehrus 

 americanus. Enlarged. 



FIG. 207. Broad-shouldered Water- 

 strider, Rhago-velia coUaris, Enlarged. 



256 



