CHAP. XVir. FAMILIES OF HEMIPTERA. 117 



CHAPTER XVII. 

 ORDER V. HEMIPTERA, (True Bugs.) 



SUB-ORDER II. HETEROPTERA. (Dissimilar-winged Bugs.) 



WATER-BOATMEN (Notonectidae). These insects have con- 

 vex bodies and are provided with four wings; the hind legs 

 are very long and fringed; the antennae are minute and con- 

 cealed in cavities; the feet are two or three-jointed; the ocelli 

 are wanting, and the head is nearly as wide as the body. 



These insects live in the water and are predaceous in their 

 habits; they seldom exceed six lines in length. 



WATER-SCORPIONS (Nepidss). These insects have very flat 

 bodies and are furnished with four wings; the anterior legs 

 -are fitted for grasping, and are placed well forward; the 

 -antennae are minute and are concealed in cavities; the feet 

 are one or two-jointed, and the ocelli are wanting, 



These insects are aquatic, and feed upon other insects; they 

 are usually quite large. 



GALGULA-BUGS (Galgulidse). In this Family the body is 

 broad and flat and provided with four wings; the antennae 

 are minute and concealed in cavities; the eyes are placed at 

 the outer end of a stem or pedicel; the ocelli are present; the 

 feet are one or two-jointed, and the anterior thighs are enlarged. 



These insects live in damp situations and are supposed to 

 feed upon other insects; they are ordinarily smaller (although 

 of nearly the same form) than the representation in Fig. 304. 



WATER-MEASURERS (Hydrometridx) . These insects 'have 

 a long slender body, and are usually provided with four wings, 

 but in a few species these organs are wanting; the antennae 

 are quite long and slender; the ocelli are sometimes wanting; 

 the feet are two or three-jointed, and the four posterior legs 

 are generally very long and slender. 



The insects are aquatic, and the adults may frequently be 

 seen running over the surface of the water; they feed upon 

 other insects and are usually less than six lines long. 



