222 



Aquatic Organisms 





eggs are often laid on the under side of floating leaves 

 of pondwccds. 



The diving beetles (Dytiscidae and 



■ 1 Hydrophilidae) are by far the most num- 



erous and important of the aquatic 



beetles. These swarm in every pond 



and pool, and are among the most 



I important carnivores of all such waters. 



They range in size from the big brown 



i Dytiscus (fig. 129) down to little fellows 



I a millimeter long. Their prevailing 



colors are brown or black, but many of 



Fig. 130. One of the lesser forms are prettily flecked and 



the lesser diving 

 beetles, Hydro- 

 porus, seven 

 times natural 

 size. 



streaked with 

 yellow (fig. 130). 

 The eggs of the 

 Dytiscus and of 

 other members 

 of its family are 

 inserted singly 

 into punctures in 

 the tissues of 

 living plants (fig. 

 131). Those of 

 the Hydrophilids 

 are for the most 

 part inclosed in 

 whitish silken 

 cocoons attached 



*-.0 plants near the Pig. 131. Eggs of the diving beetle, 



.,,^o^« r^f fh^ Dytiscus, in submerged leafstalks, nearly 



aliricice 01 Lite readv for hatching: the larva s hows 



Water. through the shell. (From Matheson) 



