ZooL.-VOL. III.] SNODGRASS—DOLICHOPODID HYPOPYGIUM. 28 1 



The penis (fig. 8,^.) is a long slender curved rod with 

 the tip slightly curved ventrally. The sheath is almost 

 completely tubular. 



The posterior clasping appendages are three in number 

 on each side (figs. 8 and 5, a, b, and b'). They arise so 

 far forward on the inner surfaces of the lateral walls of the 

 genital chamber that they are mostly concealed within the 

 latter. The upper appendage of each lateral set is a wide 

 flat plate, concave on the upper border, strongly convex 

 below. It is directed backward and ends in a strong thick 

 pedicellaria-like head (fig. 5, a). This appearance is due 

 to two large terminal hooks, the upper gently decurved, 

 the lower strongly bent upward. The other two append- 

 ages (3 and b') of the same side arise just below the 

 upper. Their bases are superposed, i. e., one is lateral of 

 the other (fig. 5), but the two are independently movable. 

 The outer one {b) is the larger and is almost V-shaped. It 

 extends posteriorly and downward from its base, and then 

 turns upward and posteriorly, ending in a slight enlargement 

 turned somewhat inward and bearing three large thick 

 curved hairs. The inner appendage {b') is much smaller 

 than the outer. It has a wide base, but rapidly tapers 

 downward and backward, ending in a blunt, slightly 

 upturned point bearing one long hair. 



The tenth segment (fig. 8, x) consists of two very small 

 membranous paranal or lateral lobes, and of a median 

 elongate triangular ventral lobe between the bases of these. 

 The three are almost entirely concealed within the dorsal 

 part of the genital chamber. 



Tachytrechus vorax Loew. 

 Plate XXXII, Figs. 7-10. 



The seventh segment in this species is large and funnel- 

 shaped with the larger end posterior (fig. 9, vii) . The eighth 

 segment is triangular in lateral view (fig. 9, viii), the lower 

 end being prolonged sharply downward. The hypopygium 

 (fig. 9, ix) is somewhat elongate. The sheath of the penis 



