78 INSECT TRANSFORMATION 



modified labium or beak, enclosing the piercing mandibles and 

 maxillae, as already described for the aphids ; this beak, when 

 not in use, extends backwards between the bases of the legs, 

 its tip reaching the middle of the abdomen. The prothorax 

 is broad and collar-like, wider behind than in front with pro- 

 minent " shoulders ", covering the front region (scutum) of 

 the mesothorax, of which the triangular scutellum with apex 

 directed backwards is the most conspicuous feature. The 

 forewings borne on this segment have, in bugs generally the 

 tip membranous and the basal two-thirds of firm texture, this 

 latter region being divided into a costal and central area (the 

 corium), and a dorsal area (the clavus) marked out by a straight 

 suture ; in the capsid bugs, a small but distinct third area 

 (the cuneus), is found between corium and membrane. The 

 forewings, so largely firm and rigid, serve as protective coverings 

 for the membranous hindwings (attached to the metathorax), 

 which lie beneath them when not in use for flight. In this 

 resting position the clavus of each forewing lies close against 

 the scutellum, and the wings lying flat over the abdomen hide 

 completely that region of the body. The legs are relatively 

 long and slender, with three segments to each foot. Beneath 

 the tip of the female's abdomen, in a narrow groove, lies the 

 ovipositor ; this consists of blade-like processes by means of 

 which the insect can lay her eggs (Fig. 42 a) partly imbedded 

 in soft plant-tissues. 



The newly-hatched young of a capsid bug is in most respects 

 a miniature of its parent. In a species of Plesiocoris (Fig. 

 42 g) of which the life-history has been traced in some detail 1 

 it is a minute green insect about a millimetre (Jg- inch) in 

 length with feelers having the same segmentation as in the 

 adult, but relatively thicker, and the head being more acutely 

 triangular. The three segments of the thorax are undifferen- 

 tiated, and there is no trace of wing-rudiments ; each foot has 

 as yet only two segments (Fig. 42 b). After its first moult, 

 the little bug (Fig. 42 c) becomes 1-5 mm. in length ; in 

 the next stage (Fig. 42 d) the corners of the mesothorax and 

 metathorax are produced into blunt rounded lobes, the first 

 indication of wing-rudiments. In its fourth stage the young 



1 F. R. Petherbridge and M. A. Husain : "A Study of the Capsid Bugs 

 found on Apple Trees ". Ann. Appl. Biol., Vol. IV., 1918. 



