Hemiptera 



191 



one-segmented ; those of the middle and hind pairs bear two claws. 

 Those of the front pair are clawless, curved, and sharp, the power- 

 ful forelegs being modified for seizing prey, as the Nepidje feed on 

 smaller inhabitants of the water. Only 

 two species inhabit our islands — one 

 (^Nc'pL! the " w^ater-scorpion") has a broad 

 and flat body, while the other (^Ranatra) 

 is very long and narrow. Some tropical 

 Nepids attain a gigantic size. 



Notonectidae. — The Notonectlda or 

 "Water-boatmen" are distinguished 

 from the Naucoridse and Nepidae by 

 the insertion of their fore-legs at the 

 hinder edge of the prosternum. The 

 body is convex ; the head large and 

 broad witii prominent eyes and four- 

 segmented feelers, the beak short and 

 conical with three or four segments ; 

 the scutellum large ; the forewings well- 

 developed and reaching to the tip of the 

 hind-body ; and the feet with two 

 distinct segments. 



Corixidae. — The Corixida are a family 

 of small water-bugs, distinguished by 

 their elongate oval, flattened form and 

 short unjointed beaks. The head is very wide, wider than the pro- 

 notum. The fore-legs are short and thick, the feet consisting of a 

 single flattened segment, which bears, in the male, a row of small 

 strong teeth ; these drawn across the sharp edge of the face produce a 

 shrill chirping note. The middle legs are long with one-segmented, 

 clawed feet, and the hind-legs are also long, the feet being two- 

 segmented and flattened and fringed so as to serve as oars. The 

 hinder abdominal segments in the male are not symmetrical, and 

 the sixth segment bears on its upper side a small stalked plate 

 furnished \vith rows of teeth ; this organ is called the strigil, but its 

 function is unknown. The Corixidae are distributed in all parts 

 of the world. 



Fig. 105. — Louse {Pedicuhts 

 vestimcnti. Leach) Europe. 

 Magnified 15 times. From 

 Osborn (after Denny), Bull. 

 5 (n.s.) Div. Ent. U.S. Dept. 

 Agr. 



Sub-Order B. Anoplura. 



The Anoplura or true Lice (fig. 105) are small, 

 parasitic insects, distinguished from all other Hemip- 

 tera by the absence of all vestiges of wings and the 

 unjointed fleshy beak (fig. 106) which is provided with 

 a circle of booklets near the base, giving a firm hold 



