WATER-SCORPIONS 353 



or short-winged. The eggs are enveloped in mucilage, 

 and attached to submerged plants. 



We pass next to those aquatic Rhynchota which 

 seek their food beneath the surface of the water.. 

 Though primarily adapted to a submerged life, they 

 leave the water at times to seek a fresh haunt, and 

 fly very well. These excursions are usually made at 

 night. 



The family Nepidae (Water Scorpions) includes 

 two very common forms, Nepa and Ranatra, which 

 agree in the possession of fore-legs completely modi- 

 fied as instruments for seizing live prey. The antennae 

 are short and concealed. The respiratory tube con- 

 sists of two long spines. Each spine is hollowed, and 

 forms a demi-canal. When brought together, they 

 make a tube, whose continuity is maintained by a 

 multitude of hook-like bristles which project from the 

 opposed edges. The tube conducts air to a pair of 

 spiracles situated near the hinder end of the body 

 and at the base of the tube ; these are the only 

 apertures for the admission of air. A Nepa or 

 Ranatra may sometimes be seen to creep backwards 

 along a submerged weed until the tip of its breathing- 

 tube breaks the surface of the water. The mechanism 

 for interlocking the two halves of the tube closely 

 resembles that found in the proboscis of a moth. 

 The fore-legs of Water-scorpions are solely prehensile. 

 They are strong and pointed, but without the usual 

 small terminal claws. They can be folded in two 

 like a clasp-knife. The fore-legs of Mantis, a preda- 

 tory Orthopterous Insect, furnish a close parallel in 

 many ways to those of the Nepidae. The Water- 



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