192 



INSECTS. 



The water-bugs, Hydrocorisa,are distinguished from the land-bugs,, 

 not only by their mode of life, but also by their short inconspicuous 

 antennas, and are mostly dull and uniformly coloured insects, frequenting stagnant 

 waters, where they swim some on their back, others with the back uppermost. They 

 are all comprised in two families. Of these, the water-scorpions (Nepidce) have a' 

 small narrow head, and their fore-legs are specially modified to serve as prehensile 

 organs. Whereas some swim actively, others drag themselves slowly along the 



COMMON BRITISH WATER-BUGS. 



1, The water boatman {Notoneda r/Iauca) ; 2, The water-scorpion (Xepa cinerea), with (3) its larva and (4) its eggs ; 

 5, Naucoris cimicoides; 6. Corixa geoffroyi; 7, Ranatra linearis; 8, Limndbates stagnorum; 9, Pond-skater 

 (Gerris paludu7?i), with (10) its eggs and larva? ; 11, Larva of Velia currens (nat. size). 



bottom of the ponds in which they live. They are furnished with an appendage 

 looking like a long tail, but consisting of two separate pieces, grooved on their inner 

 surface, and capable of being locked closely together to form a tube, which leads 

 to the two spiracles placed at the hind-end of the body. When the insects come 

 up to breathe, the tip of this breathing-tube may be seen emerging just at the 

 surface of the water. The form of the body is in some (Nepa) broad and flat ; in 

 others {Ranatra) elongated. The female of Nepa lays her eggs in chains on 

 aquatic plants, and each egg has seven short processes radiating from one end. 

 The eggs of the Ranatra are laid one by one in notches, which the female makes in 

 the stems of the plant. 



