88 Annals Entomological Society oj America [Vol. VI, 



in all the rest of the wing, cubitus has been dividing in the 

 opposite direction. Moreover, the end of the cephalic -branch 

 shows, as did radius and media, unmistakable evidence of a 

 doubly tracheated condition (Fig. 17). At first this was 

 considered as a mere splitting of the end of the trachea and was 

 disregarded. It appeared so constantly, however, and at times 

 extended so far back into the wing, that it refused to be ignored. 

 Again, it has been shown in other families of the Homoptera, 

 that the first and second anal veins may be widely separated- ^ 

 the first anal arising from the cubital stem. In view of these 

 facts then, it appears that the most anterior branch of the 

 upper vein represents both Cui and Cuo. That these veins 

 have coalesced outward in the regular manner, forming one 

 vein only in the adult wing, although the two tracheae are 

 distinguishable in the nymphal condition. This interpretation 

 makes the position of the anal fold in the membracid wing agree 

 with the position which it assumes in the other Hemiptera, 

 namely, along the first anal vein. If the next vein (First Anal) 

 were considered as Cuo it would make the Membracidas peculiar 

 in this respect, and not in keeping with the conditions in the 

 closely related families. 



The trachea runs parallel with media for about half the 

 length of the wing and then makes an abrupt turn downward, 

 running to the posterior margin. At this point it divides, the 

 two branches however never separating but turning together 

 outward again toward the tip. The vein which encloses them 

 follows this course without deviation. Just after the vein 

 makes the sharp turn caudad, a strong cross-vein connects it 

 with M3+4. This cross- vein (medio-cubital), as will be shown 

 later, may be of varying length but is constant and very charac- 

 teristic of the family. It well represents one of the points 

 which brings out the importance of the study of tracheation. 

 In the adult wing (Fig. 1) it might well be taken for a branch of 

 cubitus, but the nymphal wing (Fig. 18) clearly shows that it is 

 not preceded by a trachea. A careful search has been made 

 through hundreds of mounts to establish this point, and no 

 case has yet been found where this condition was not true. On 

 the theory that the principal veins are preceded by trachea 

 while the cross-veins are not, this would prove that the vein in 

 question could not be a part of cubitus. 



29. Wings of Insects, p. 249. 



