282 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



is very small and two-segmented (fig. 9, s. f. and fig. 8). 

 It lies beneath only the anterior third of the ventral part of 

 the penis. Projecting downward at the side of the penis is 

 a pair of large recurved hooks (fig. 9, h. and fig. 10), The 

 posterior lateral clasping appendages of the hypopygium 

 have the form shown in figure 7, The lobes of the tenth 

 segment (fig. 9, x) are simple and oval, 



Gnamptopsilopus filipes Loew. 

 Plate XXXIII, Figs. 4-6. 



In this species the seventh segment forms a narrow neck- 

 like stalk for the hypopygium. Its tergum (fig. 6, /. ) 

 and its sternum (5.) are small, and are separated on each 

 side by a rather wide membranous space. The eighth seg- 

 ment (fig. 6, viii) is elongate oval, the longer diameter 

 longitudinal. 



The posterior lower angles of the hypopygium are pro- 

 longed each into two long slender appendages (figs. 5 and 

 6, d and d''). These apparently correspond to the pos- 

 terior ventral lobes ((^) of the species so far described, but 

 there are no clasping appendages present arising from the 

 inner lateral walls of the genital chamber. The penis is 

 inclosed in a large ventral sheath (figs. 5 and 6, 5. ^.), 

 which forms a long curved cylindrical structure arising from 

 the anterior lower angle of the hypopygium. It extends 

 backward, entirely unprotected by the walls of the genital 

 chamber, to the posterior end of the long posterior ventral 

 hypopygial lobes. The penis is covered dorsally by a long 

 thin plate (fig. 5, d. s. f.) fitting closely upon the dorsal 

 side of the ventral sheath. 



The two dorso-lateral lobes of the tenth segment (figs. 5 

 and 6, x and fig. 4) are united by their median edges almost 

 to their posterior ends, leaving only two small flaring terminal 

 flaps free. The inner posterior margin of each of these 

 bears a close row of short curved spike-like hairs. On 

 each lateral aspect of the undivided part is an oblique row 

 of long stiff slender hairs (fig. 4). 



