Packard] INSECTS OF THE POND AND STREAM. 135 



be subaquatic, and in its structure and habits connects the 

 Carabids with tlie Dytiscidre. 



Out of the immense number of species of butterflies and 

 moths, but three or four genera are known to be aquatic. 

 The larvjB of Hydrocampa, Cataclysta and Paraponyx, small 

 moths of the family of PyralidiB, live in the water on the 

 leaves of aquatic plants, the caterpillar of Paraponyx being 

 provided both with branchite and spiracles. M. Bar has 

 lately disco^'ered in French Guiana a hairy caterpillar which 



Fig. 97. 



A Tardigrade. 



lives in the water, and resembles that of our Arctia or 

 "woolly bear." It has no tracheal branchiae, and all the 

 spiracles except those on the segment behind the head and a 

 pair on the end of the body are smaller than usual. 



There uic no truly aquatic Hj-menoptera or Orthoptera. 

 The aquatic Ileniiptcra, such as Gerris, Notonecta, a Corixa 

 and a few other forms, all breathe atmospheric air, though 

 the stigmata may be elongated and otherwise modified for 

 the purpose. One spider, the Argyroneta of Europe, is 



7 



