294 



THE WINGS OF HETEROPTERA 



wing which would be traversed by Trachea Ri were it well developed. 

 Trachea Ri is present, but is reduced to a vestigial condition. It is evident 

 that a supplanting of vein Ri by the subcosta takes place here as in Cicada. 

 Trachea Rg has its characteristic bend at the base, and is two-branched. 

 Trachea M is typical except that the branch M3 coalesces with Mi +2 for a 

 short distance. Trachea Cu is six-branched ; it is evident that a specializa- 

 tion by addition has taken place here. Only a single anal trachea has been 

 preserved. 



The hind wing of the same nymph (Fig. 303) presents a very similar 

 arrangement of tracheae, except that their branches are reduced. 



(c) THE VEINS AND FURROWS OF AN ADULT WING 



In those pentatomids in which we have been able to trare the courses of 

 the trachese of the wings, the wing-veins of the adult are comparatively 

 inconspicuous. It is better on this account to take as an illustration of an 

 adult wing that of a coreid, Harmostes reflexulus, in which the tracheae 

 are distinctly visible within well-developed veins ; the courses of the veins 

 are indicated in Fig. 304. 



Fig. 304. — Fore wing of an adult coreid, Homostes reflexus 

 (After C. & N.). 



The median furrow of the wing is in its typical position between radius 

 and media. In the pentatomids that we have studied it is more closely 

 parallel with the radius and extends across the radial sector, showing that 

 its position is not determined by the courses of the veins. The anal furrow 

 is in front of cubitus instead of in its more usual position, behind this vein. 

 In fact, in all of the Heteroptera that we have examined, when an anal 

 furrow is distinctly developed it is in front of the cubitus. 



The anal furrow is the line of division between the corium and the 

 clavus; the median furrow when well-developed separates the embolium 

 from the corium ; and the development of a nodal furrow limits the corium 

 still more by cutting off the cuncus. 



