216 R. E. SNODGRASS. 



The penis and central vesicle are ordinary. The guard of the 

 penis is an elongate bar widened distally into a triangular plate, 

 ending in a median point and two longer club shaped lateral arms. 

 A median, dorsal groove runs along its entire length (fig. 93). 



The anal tube is exceptionally large (fig. 90), being wide basally 

 and very long, so that it projects far out of the genital chamber (fig. 

 91, a. L). 



Tipula bicornis (PI. XIV. figs. 94, 95, 96, 97, 98, 99, 100, 101). 



The eighth sternum is greatly elongated and produced posteriorly. 

 The sides are convergent, but the end is truncate and bears a flat 

 brush of long hairs. 



The tergum of the hypopygium (fig. 101) is very long, widest at 

 the base, slightly tapering distally. The posterior margin is notched 

 mesially and on each side is produced into a tapering horndike pro- 

 cess, projecting outward and posteriorly. On account of the great 

 length of the tergum the hypopygium is much longer above than it 

 is below. Between the tergum and the pleurum on each side (fig. 

 94) is a wide triangular membranous area. From a point somewhat 

 beyond the middle of each lateral margin of the tergum a chitinous 

 band extends downward and posteriorly through the membrane just 

 described and unites with the side of a small trapezoidal plate on the 

 ventral wall of the anal tube (fig. 100). 



The pleura are triangular plates distinct from the sternum. Each 

 has a wide convex anterior edge. The other two edges are concave. 

 From the upper angle there projects posteriorly and upwardly a 

 sharp tapering process (fig. 94). This is simply a prolongation of 

 the pleurum itself. 



There are three apical appendages on each side (fig. 98). The 

 first (A) is short, cylindrical and very slender. The second (B) is 

 nearly twice as long as the first. It is an elongate stalkdike struc- 

 ture, with an enlarged, distally rounded, capdike head. The third 

 (C) arises from the posterior edge of the base of the second. It con- 

 sists of a narrow basal peduncle, a triangular, flattened plate beyond 

 this, and of a slender distal arm with a terminal enlargement. 



Just below each pleurum there projects posteriorly from the ster- 

 num a small flattened truncated lobe (fig. 94). Each of these pro- 

 cesses bears on its inner side a small appendage (fig. 96), which car- 

 ries a bunch of long, spirally twisted hairs on a knob near its inner 

 end. 



