354 NATURAL HISTORY OF AQUATIC INSECTS CH. 



scorpions are rather sluggish in their movements, and 

 creep about in a leisurely way on the bottom of 

 ponds. Nepa feeds mostly on small Insects, Ranatra 

 upon the Water-flea (Daphnia) and other aquatic 

 animals. The form of the body differs remarkably 

 in the two genera. Nepa is broad and flat, Ranatra 



n 



FIG. 107. A, Water-scorpion, Nepa cinerea. B, fore leg, enlarged, showing 

 groove in femur which receives the rest of the limb. C, egg. 



extremely elongate. Ranatra is nearly black ; Nepa 

 of a dark ash-colour, and very inconspicuous except 

 when the wings are spread, when the top of the 

 abdomen is seen to be of a brick-red. The eggs of 

 both are laid one by one in holes pierced in the leaves 

 of aquatic plants, or in notches cut in submerged 



stalks. From one end of the egg stand out filaments 



