THE WATER SCORPIONS 



(Family Nepida.) 



Fig. 169. Nepa cinerea Linn : a, adult; b, front 



leg, showing groove to receive rest of 



limb ; c, egg. (After Miall.) 



The Nepids have been called "water scorpions" because 

 their fore legs are swollen and fitted for grasping, and rather 

 distantly resemble the cheliceres of a scorpion. The anal end of 

 the body bears two long half-tubes which, when united, form a 

 tube to convey air to the insect when the rest of the body is 

 under water. The water scorpions are either flat and oval 01 

 they are long and thin. Those of the former shape belong to the 

 genus Nepa, and of the latter to the genus Ranatra. As with 

 the water boatmen and the back swimmers, these insects are 

 predatory, and a large share of their food is the eggs of fish, but 

 they also attack small fish and other water insects. 



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