BUGS. 251 



is crossed by zigzag lines at base, and by others which become more sliender and 

 straight towards the tip. Similar lines on the corium are more sinuous and interrupted 

 towards the inner margin. The costal area is blackish at base, and there is a spot of 

 the same color behind the middle. Each side of the presternum there is a large black 

 spot, and a fuscous cloud on the middle and posterior coxae. The palse are curved, a 

 little widened in the middle, and acute at tip. It measures fully five-twelfths of an 

 inch to the end of the wing-covers. The palss of the male are out off obliquely at 

 tip, and the sides are not curved, but nearly parallel. In this species the frontal 

 fovea is oblong, not very deep, and extends up to a point about the middle of the 

 eyes. 



These insects are truly aquatic, but they occasionally leave the water, particularly 

 when they find it to be drying up, and during their nocturnal flight are drawn to the 

 lights in our houses, into which they dash with headlong precipitation. They frequent 

 almost every variety of water, from the briny lakes of Utah and California to the 

 clearest mountain streams of our northern territories ; but they are not confined to this 

 country, and are distributed from the sub-arctic regions of both hemispheres to 

 southern Africa on the eastern, and to the Argentine Confederation on the western 

 continent. 



The greater number of species thus far known have been obtained from Europe 

 and North America. In the middle States there are summer forms and winter forms. 

 The latter are chiefly those which belong to Cajiada and the extreme north, while the 

 others have a local distribution concurrent to a certain degree with the temperature of 

 the water in which they are hatched. One of these, the C. interrupta, may be found 

 in puddles and sun-heated streams from New York city to Rio, Brazil. In Mexico, 

 Central America, the West Indies, and southwestern United States there is an assem- 

 blage of species which is rendered quite remarkable by the pale dull vermiculate 

 markings which prevail over nearly the entire hemelytra. About one hundred and 

 fifty species have already been discovered, and new ones turn up wherever explorations 

 are conducted with intelligent care. 



Few insects are more sprightly, and the aquarium acquires a new interest by the 

 introduction of these easily obtainable creatures. They live on the bottom in puddles, 

 ponds, and running waters, but it is especially of interest to observe their habits upon 

 the bed of a bayed-out part of a stream, where there is no current. In such places 

 they may be seen at home, balanced with the neatest delicacy by the tips of their 

 intermediate feet, stationed in the midst of their young at intervals of a few inches ; 

 then, by reason of some disturbance, dashing away with rapid strokes of the posterior 

 paddles, and arising to the surface, perchance to take in a fresh supply of the external 

 air. There, resting horizontally for an instant, with the long middle feet extended 

 forward, the sides and ventral margin become glazed with an air-film which shines 

 like translucent silver. The head and prothorax are capable of much freedom of 

 motion, and at such times both of these are lifted to admit the air to the dorsal 

 spiracles, which are situated on the sides above the legs. The genus Sigara also 

 belongs to this family, and may be distinguished from Corisa,, by the small but 

 uncovered scutellum. 



The family Notonectid^ is composed of perfectly aquatic forms, differin^from 

 all others in the persistent habit of swimming on their back. They are much deeper 

 bodied than other Heteroptera which live in the water, and while being oval in form 

 with the apex of the wing-covers conical, have the convexity of the surface above. 



