PACKARD] INSECTS OF THE POND AND STREAM. 141 



water and an orifice is formed by the separation of the liairs 

 at the end of the keel, Avhich form the larger part of the 

 mouth of the orifice, the remainder being composed of the 

 hairs fringing the movable terminal plates of the body. 

 The air thus passes in between the false deck of hairs and 

 the under side of the body. When the insect is taken out 

 of the water the hairs cling to the sides of the body, reveal- 

 ing very distinctly the breathing holes. Some air occasion- 

 ally penetrates under the elytra and remains there most of 

 the time. Often the whole under side of the bod}'' between 

 the pairs of legs is a continuous bubble, like a mass of quick- 

 silver or molten lead. The Notonccta often rises for a new 

 supply of air before the old is exhausted. 



"While handling Notouecta thoughtless of its reputed sting, 

 in a quiet business-like way it inserted its beak in my thumb, 

 the pain almost as severe as the p,^, ^.^^ 



sting of a Avasp, and lasting for 

 five minutes. The pain was too 

 acute and benumbing not to be 

 the elTect of a poison. If no 

 poison sac will yet be found in 

 the head, then the saliva must 

 be an acrid poison. By this 

 poisonous sting it must para- 

 lyze its victims. 



Another water bug, the Co- 

 rixa (Fig. 104, enlarged), is less 



tame and does not come to the surface nearly as often as 

 Notonccta. It receives its suppl^^ of air in an instant and 

 darts down to the bottom. It does not swim in an inverted 

 position. It takes in the air so suddenly that it is impos- 

 sible without long and patient observation to see the mode, 

 which we have been unable to find described. It rises to 

 the surface in a horizontal position and no sooner is the sur- 

 face reached than it darts to the bottom, and in one instance 



13 



Corixa. 



