206 R. E. SNODGRASS. 



(fig. 128). The hypopygium is relatively small, and projects up- 

 ward and posteriorly from the eighth segment. The sternum of the 

 latter is not specially produced beneath it. 



The tergum and sternum of the hypopygium are not separate, and 

 the pleural plates are not distinct from the sternum. Pleural 

 sutures are present. The tergal aspect (fig. 130) is quadrate, roundly 

 concave anteriorly, produced into three processes posteriorly, one of 

 which is wide and median, the other two hook-like and situated 

 nearer the lateral margin. The sternal parts (fig. 129) have essen- 

 tially the same structure as in Tipula bella. The anterior margin 

 is strongly convex. Separated from it by a narrow chitinous band 

 is a large membranous area, and back of this is the posterior mar- 

 gin forming a deep re entrant angle. The pleural sutures (fig. 129, 

 p. s.) running forward and then turning outward a short distance, 

 set off two prominent mesal lobes of the sternum having free rounded 

 apices. The apical appendages are three in number. The first (fig. 

 128, A) is triangular and attached by one of the angles. The other 

 two consist of irregular plates mostly fused with one another. 



The central vesicle is of ordinary shape. The posterior arms are 

 somewhat long, and the apodemes relatively small. The v shaped 

 bar between the posterior arms of the vesicle is extremely large ; it 

 reaches on each side to the lateral walls of the genital chamber and 

 embraces the base of the anal tube between its arms. 



The guard of the penis arises from the floor of the genital cham- 

 ber, above the anterior end of the sternal notch. It has the ordi- 

 nary slender, tapering form, with a longitudinal groove above (fig. 

 131, p. g.). Basally it is triangularly enlarged. From this enlarge- 

 ment two short horn like roots project anteriorly (a). From the 

 sides two large, free, elongate, flat, twisted arms proceeds posteriorly 

 (6). Each is widest near middle, curved inward distally, and ends 

 in a small, blunt, hook-like point. The tips are visible below, from 

 the outside of the hypopygium, projecting beyond the ends of the 

 ventral sternal lobes (fig. 129, b). 



Tipula tephrocephala Loew (PI. XV, figs. 118, 120, 122). 



The eighth segment is not specially modified. The tergum is rela- 

 tively large and the sternum is no larger than the seventh (fig. 118). 



The tergum of the hypopygium (fig. 120) has a simple quadrate 

 form with two slender, divergent arms projecting posteriorly from 

 the posterior margin. The lateral sternal plates are separated below 



