194 



Aquatic Organisms 



in such rapid succession that the body is moved 

 smoothly forward. A few water-mites that dwell in the 

 open water of lakes are transparent, like other 

 members of open-water plancton. 



Water-mites are nearly all parasitic: they puncture 

 the skin and suck the blood of larger aquatic animals. 

 Certain of them are common on the gills of mussels: 

 others on the intersegmental membranes of insects. 



Fig. ioi. Water mites of the genus Limnochares 



Nothing is more common than to find clusters of red 

 mites hanging conspicuously at the sutures of back- 

 swimmers and other water insects. 



Many mites lay their minute eggs on the surface of 

 the leaves of water plants. Their young on hatching 

 have but three pairs of legs. 



