.362 ORDERS OF PTILOTA. 



of unequal consistence;, the basal portion being coriaceous, 

 and the terminal half membranous ; and the second section 

 having the ^ing-covers deflexed and of equal consistence 

 throughout. Moreover, in the first of these divisions the 

 rostrum, or promuscis, as it is termed by Mr. Kirby, arises 

 at the front of the under-side of the head, whereas in the 

 second it springs from its posterior portion, near the base of 

 the fore legs, and sometimes appearing pectoral. In the 

 former, the hemelytra, besides their different substance, as 

 well as the wings, cross each other ; while in the latter, the 

 organs of flight are deflexed, and do not lap over each other 

 at all. The antennae, also, of the former are often long, and 

 do not terminate in a bristle ; whilst in the other, with few 

 exceptions, they are very short and setigerous. In the 

 Heteroptera the body is depressed and flat; in the Homoptera 

 convex and thick. In the former the scutellum is one of 

 the principal features of the trunk ; in the latter not at all 

 remarkable. 



The first of these sub-orders, Heteroptera, is divisible into 

 two primary divisions, namely, 1. the Geocorisa, having the 

 antennae long and exposed, and 2. the Hydrocorisa, having 

 antenna? short and concealed. 



The former comprises the very numerous species of field 

 and house bugs, divided into numerous families or rather sub- 

 families ; the latter comprises such species as reside in the 

 water, and which are predaceous in their habits, feeding upon 

 other insects, which they seize by means of their fore-legs, 

 serving as claws, the extremities folding upon the basal 

 portion- The latter division comprises two families, the Ne- 

 pidts, or water-scorpions, so named from the cheliferous struc- 

 ture of the fore-legs ; and the Notonectidee, or boat-flies, so 

 named from the boat-like form of the body, and the oar-like 

 structure of the hind legs. 



The second sub-order, Homoptera, consists of numerous 



