600 PROCEEDINGS -OF THE NATIONAL MUSEUM. vol. xxix. 



rowintj' of the wiiiji', liavH^ migrated to the apex of the wing, so as to 

 stiffen it, while in tlie genera Blennociinipa and Perlclista Kj extends 

 around the apex. In the Cephidw and Cinibicinse R3 has retained its 

 primitive position distinctly before the apex of the wing- while Rj has 

 been extended spur-like to the apex. The genus IloplocmnpaV^'g. 01) 

 shows a similar condition, except that the prominent spur-like tip 

 has not been developed. 0?'i/t<stis (fig. 97), Trerae,r (fig. 91), Paururus 

 (fig. 86), Monocteniis (fig. 67), DJelocerm (fig. 79), and PacJi.ylota (fig. 

 77) show a modification of the condition found in Ble^inocampa and 

 Peridista. In these genera Rj and R., have migrated to the apex of 

 the wing, but the apical half of the vein R^ atrophied, causing the cell 

 Ri+2 to return to its original condition, open at the margin. The 

 genera Xerk (fig. <S9), Hylotoma (fig. 76), Lahidarge (fig. 78), Perga 

 fig. 84), Perreyia (fig. 80), and LohoceTcm (fig. 82) show a still different 

 type. Here R3 ends distinctly before the margin of the wing while 

 Rj is continued to the apex, but in the course of its development was 

 pulled away from the margin for a considerable distance, forming an 

 appendiculate cell in the same way that it is formed in the front wing. 



The second part of the vein R + M, Rs+ M, very soon divides into 

 Rs and M. In all the wings observed the free part of R^ is wanting; 

 also R5, except in the genera Megaxyela, Odontophyes^ and Macoxyela. 

 R3 occupies a position similar to that found in the front wings; the 

 onl}^ marked modification is the point at which it reaches the margin, 

 and this was full}' discussed above. 



The tip of the fourth branch of radius has combined with R5+ Mj as 

 in the forewing, while the free part of R^ is a transverse vein extend- 

 ing between R3 and R5+ Mj. In the Xyelid^ (figs- 31-36), Lydidse 

 (figs. 36-43), and Megalodontida^ (fig. 92), it is situated near the margin 

 of the wing, but in most Teuthredinoidea it has migrated toward the 

 base of the wing; while in such genera as Lohocenm (fig. 82), Dolerris 

 (fig. 49), Pteronus (fig. Q^)^ and Chidrvs (fig. 66), it is situated in a line 

 with the costal area of hooks. The free part of R^ is entirel}- wanting 

 in the subfamilies Blennocampinas (fig. 72), PhyllotomintB (fig. 54), 

 Fenusinai (tig. 74), and the genera Tetratneura and AGidophom. 



The radio-medial cross vein is wanting in all the genera observed. 



THE MEDIAL AREA. 



In all the wings examined, except in Slrex (figs. 87-88), and Mano- 

 Kyela (fig. 34), the vein M is coalesced with the radial sector for a 

 greater or less distance. This is very different from the conditions 

 found in the front wing, where M always arises from R some distance 

 before the origin of the radial sector. In Sirex and Manoxyela M 

 arises from R distinctly before the origin of the sector, but much 

 nearer to it than is the case in the front wings of all other Teuthredi- 

 noidea. In Paururus (fig. 86) and Xerl.s (fig. 89) M arises from the 

 sector at or just beyond its origin; in Macroxyela (fig. 33) it extends 



