HEMIPTERA 187 



rudiments of the wings are seen, and the active pupal stage is 

 reached. In due course the pupa casts its skin, and the adult, 

 with fully developed wings, appears. The mouth is converted 

 into a suctorial apparatus, slender and pointed for piercing the 

 tissues of plants or, in the carnivorous forms, the skin of their 

 prey. Four wings are generally present, and compound eyes of 

 moderate size. They have a world-wide distribution, though 

 they are most numerous and attain their largest size, most curi- 

 ous forms and brightest colours in the tropics. 



The Shield Bugs live upon plants, trees and shrubs, feeding 

 on the juices which they suck out of the soft tissues by the aid 

 of their slender beaks. One of the best known is the Red-legged 

 Bug (Tropicoris ruftpes), which measures about f inch in length. 

 The Colewort Bug (Strachia oleracia) is^of a blue or greenish colour, 

 variegated in the female with red and in the male with white 

 markings, and is to be found on wild and cultivated cruciferous 

 plants. 



The Gerridae, in their habits, may be said to link the Land Bugs 

 with the Water Bugs, and during the summer months may be 

 seen running actively over the surface of every pond and slow- 

 moving stream. These insects have boat-shaped bodies, and the 

 typical forms, such as the Pond Skater (Gerris lacustris), which 

 frequent most ponds and streams, literally row themselves along 

 the surface of the water by means of their long legs, their power 

 of floating being aided by a coating of hair which covers the lower 

 surface of the body and carries with it a supply of air. They 

 chase and feed upon other insects. 



The Nepidae, or Water Scorpions, are rather sluggish in their 

 movements, and creep about in a cautious way at the bottom of 

 ponds and slow-moving streams. The front legs of these insects 

 are completely modified as instruments for the capture of living 

 prey ; they are strong, pointed, minus the usual small claws, and 

 can be folded back like a clasp-knife ; indeed, in their shape, and 

 the manner in which they are used, they closely resemble the fore- 

 legs of the curious Praying Insect, or Mantis, which belongs to 

 the Orthoptera. The Common Water Scorpion (Nepa cinerea) is 

 about i inch long, and has an oblong, flat body, terminated by a 

 pair of tail-like organs which, when put together, form a long, 

 slender breathing tube. The Water Stick Insect (Ranatra linearis) 



