FRESH- WATER REPTILES AND INSECTS. 75 



to the surface of the water, with his legs extended as if 

 ready to move off. He is then watching for a victim, 

 and if one comes within reach, he darts upon it with 

 rapidity, and is out of sight with it in a moment, carrying 

 it to some hiding-place, where he sucks out all its living 

 juices. And he in turn becomes the food of — 



The Margined Beetle (Dyticus marginalis)^ a singular, 

 scorpion-like creature, in its larva state, that it would be 

 better to avoid altogether in your tank. When it has 

 grown into a V/ ater Beetle it is pretty, and when well 

 fed, by suspending a piece of meat to a string for its use, 

 may be innocent. In its larva state, it is so destructive 

 and so homely, that it is known as the Water Tiger or 

 Water Devil, and should a boat-fly approach within its 

 range, the intruder is torn piecemeal in an instant. At 

 the proper time, this Tiger builds himself a case, some- 

 thing like that of a chrysalis when about to be trans- 

 formed into a butterfly. In this case his change occurs, 

 and he comes forth a Diving Beetle, emerging from the 

 mud at the bottom of the stream where he has buried 

 himself, with shining wings and a form altogether much 

 more prepossessing than his original. It is unsafe, how- 

 ever, to keep him, or in fact, any of the water beetles, in 

 a tank with fish. 



The Oaddis-worms are the larva stages of the various 

 species of the Phryagaiiea. The angler is well acquainted 

 with it, as it makes its home in running streams, and 

 resides in a grotto or cell which it constructs around its 



