AQUATIC INSECTS 



The line along which the cap will open is marked on the egg 

 shell by a white crescent-shaped streak. 



These bugs thrive in dishes of water if they are kept sup- 

 plied with food, such as insects and pond snails, and are 

 enclosed by a screen top. The eggs are so large that the young 

 Benacus and its hatching can be clearly seen with the naked 

 eye. The plant stalk bearing the cluster of eggs containing 

 embryos should be set up in a natural position in an aquarium, 

 when the whole process can be watched. 



Water scorpions, Family Nepidae. — The water scorpions 

 have two long tail filaments which form a breathing tube, and 

 thev can rest on the bottom or some submerged support with 

 the tube thrust up through the surface film for air. No other 

 water-bugs have such a contrivance. 



Fig. 178. — Water scorpion, Nepa apiculata, 

 showing its clutching fro^t legs and the tail-pieces 

 held together to make a/ breathing tube. 



Water scorpion, Nepa apiculata. — This dead-looking bug 

 lurks among muddy leaves along the pond margin. Its 

 apparent inactivity is a watchful waiting for mayfly nymphs, 

 snails or crustaceans which it can clutch with its front legs 

 (Fig. 178) and then suck till only their husks are left. Water 

 scorpions do not lose their appetites easily and their fierce 

 sallies upon their neighbors can often be v/itnessed even in the 

 collecting pan. 



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