578 



PllOCEEDiyUS OF THE NATIONAL MUSEUM. 



VOL. XXIX. 



forward to the base of 1st A, combines with it, and closes the first 

 anal cell at base as well as at apex (figs. 4—5). The further modifi- 

 cations of the anal veins and cells are all the result of this coalescence 

 continued at apex and base until the free part of 2d A appears as a 

 cross vein just beyond the middle of the cell, while the apex of the 

 cell bears an elongate, simple, spur-like vein formed by the combined 



u ^ 



2d A+3d'A'Ut A 



Fig. 2. — Modified hypothetical type. 



union of the three anal veins (figs. 7-8). We thus have formed what 

 is known to the students of the Tenthredinoidea as the lanceolate 

 cell, which is in reality two very difi'erent cells. The modifications 

 of the lanceolate cell serve as excellent characters for tracing the 

 phylogeny of the family Tenthredinida? and for dividing it into smaller 

 groups. 



The cubitus, Cu, is a forked vein lying just in front of the three 

 anal veins (fig. 1). The two branches of cubitus, Cuj and Cu.^, migrate 



1st A^2d A^Sd A 



Fig. 3. — Modified hypothetical type. 



toward the com})ined tip of the anal veins (fig. 3) and coalesce with it 

 (figs. \-h). By this means, first, the cell Cu and then the cell Cuj are 

 closed at the margin of the wing. The branches of cubitus after 

 combining with the united tip of the anal veins, follow along the front 

 margin of 1st A, coalescing with it more and more, and at the same 

 time crowding the cells Cu and Cu^ farther and farther away from the 



