208 R. E. SNODGRASS. 



the base two long, slender, slightly curved, tapering arms (a) pro- 

 ject backward below the guard. Below these is a thicker, median, 

 tapering arm bent downward at its middle, and then forward in a 

 sharp hook (6). The central vesicle, penis, and anal tube are of 

 ordinary structure. 



Tipula foella Loew (PI. XVI, figs. 123, 124, 125, 126, 127). 



The hypopygium has the simpleform shown in figure 123. There 

 is no suture between tergum and sternum and there are no pleural 

 plates separate from the sternum. Pleural sutures, however, are 

 present as shown in figure 124. The tergal part is produced cau- 

 dally beyond the apical rim of the lateral and ventral parts as a 

 densely chitirious, triangular plate terminating in a decurved hook- 

 like tooth. 



Figure 124 shows a ventral view of the hypopygium with the 

 apical appendages removed. The sternal margin is thus seen to be 

 deeply notched by a deep emargination, which is linearly prolonged 

 anteriorly past the middle of the segment. Here the notch ends 

 against a large, pentagonal, membranous area which occupies nearly 

 all of the ventral surface of the segment in front of the notch, 

 leaving only a narrow arched bar of chitin forming the anterior 

 sternal margin. This is a very general structure of the sternum 

 throughout the genus. At about the middle of each lateral margin 

 of the wide part of the sternal notch, a wide, membranous suture 

 runs inward and then forward about two-thirds the distance to the 

 anterior membranous area. Here it abruptly curves outward a short 

 distance and ends. The two are the pleural sutures (fig. 124, p. s.). 

 The tip of the sternal lobe formed on each side between the suture 

 and the median notch rapidly tapers and turns mesially as a free 

 point. 



The apical appendages form one large irregularly lobed structure 

 on each side. Figure 123 shows them in their natural position 

 attached to the hypopygium. Figure 127 shows them somewhat 

 flattened out in a lateral view. The first (A) is a large bi-lobed tri- 

 angular, fleshy plate attached by an angle to the base of the others. 

 The second and third (B and C) form together a tri lobed mass lying 

 within and posterior to the first. 



The central vesicle has its ordinary ventral surface directed ante- 

 riorly. The posterior arms, hence, extend downward and the apo- 

 demes posteriorly. The penis starts forward from the vesicle, but it 



