ZooL— Vol. III.] SNODGRASS—DOLICHOPODID HYPOPYGIUM. 277 



(fig. 6, b. p.), or chitinous thickening, on the roof of the 

 genital chamber near the center. From this it curves first 

 forward and downward, close to the anterior wall of the 

 genital chamber; and then curves posteriorly, entering its 

 sheath below, through which it runs nearly straight back- 

 ward as far as the posterior end of the hypopygium. The 

 terminal part is slender, and projects beyond the tip of the 

 sheath. It is swollen apically and slightly deflexed. The 

 convex edge is strongly chitinized, forming a dark marginal 

 rib. There is a small recurved hook on the upper edge at 

 the lower end of the anterior arcuate part. From the 

 posterior part of the base there project downward two 

 cylindrical chitinous lobes, each with a funnel-shaped 

 enlargement at the end (fig. 6). 



The tenth segment (figs, i, 2, 3, x and fig. 9) is born at 

 the posterior end of the hypopygium by the space between 

 the dorsum of the latter and the roof of the genital cham- 

 ber. It consists of a small median part, carrying the anus 

 terminally and composed of a small median triangular ven- 

 tral lobe and of the bases of the two large dorso-lateral lobes. 

 The latter appear to form two expanded flat oval fleshy ap- 

 pendages terminating the hypopygium. The posterior and 

 outer margins of each are furnished with a row of large 

 strong bent hook-like hairs (fig. 9). 



Dolichopus ovatus Loew. 



Plate XXXI, Figs, i and 3. 



This species differs in no essential respect from D. cre- 

 natus. The sternum of the seventh segment (fig. i, s.) 

 is larger, and the eighth segment is more nearly circular in 

 lateral view (fig. i, viii). The clasping appendages of the 

 ninth segment (fig. 3, a and b) are similar in the two 

 species, differing in shape as shown in the figures. From 

 the posterior lower angle of each lateral wall of the genital 

 chamber a wide flat lobe (figs, i and 3, d) extends 

 downward and posteriorly, the tip being bluntly rounded 

 and turned outward. This lobe evidently represents the 



