140 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Venation of Nymphal Wing Pads and Wings of Newly Emerged Adults. 



Fore Wing {26-^ and ^^-8).— The costa, C, rises from a 

 large tracheal trunk from the thorax, proximad of the radius 

 and subcosta (fig. 3). It follows the anterior margin, but 

 drops down at the region of the stigma and fuses with the 

 subcosta. 



The subcosta, Sc, and radius, R, are fused throughout the 

 basal third of the wing, and the free portion of the first-named 

 vein is comparatively short, as it soon fuses with the costa. 



The radius is represented by a single trachea, and at its 

 base, where it is fused with the base of the subcosta, it rises 

 from the large tracheal trunk, distad of the origin of the 

 costa (fig. 3). 



Media and cubitus, M, and Cu. The media rises from the 

 main trunk just cephalad of the base of the cubitus and distad 

 of the base of the subcosta (fig. 3). It is two-branched and 

 shows its double structure throughout the distal half of the 

 pad, the two branches being close together and parallel for 

 some distance. The three tracheae, the subcosta plus radius, 

 the media and the cubitus run parallel throughout the basal 

 third of the wing. In normal position, these three tracheae are 

 very close together, as in figure 8, but in the diagram (fig. 3) 

 they are represented more widely separated to show their con- 

 nections with the main tracheal trunk from the thorax. The 

 occurrence and relative positions of these three tracheae are of 

 the greatest importance in correctly determining the homolo- 

 gies of the adult veins, as the upper of these branched veins, 

 formerly called the "upper branch of the cubitus," arises from 

 a trachea distinct from the true cubital trachea, and therefore 

 cannot be a part of the cubitus, while the trachea representing 

 the subcosta plus the radius fused is distinct from those of 

 media and cubitus, though all four veins appear as a single 

 vem in the basal portion of the adult wing. Both media and 

 cubitus are two-branched, their distal ends bending so as to 

 run parallel with the costa for some distance before fusing 

 with it, forming at some places as many as three parallel or 

 more or less intertwining lines of tracheae (fig. 3) . 



The anal fold or "claval suture" (fig. 3, af) is present as a 

 distinct trachea which fuses at its distal end with the second 

 branch of the cubitus and the costa near the posterior margin. 

 Only one anal vein (fig. 3, A) could be made out, but as this 



