500 PROCEEDINGS OF THE ACADEMY OF [Sept., 



and covered with a dense whitish pubescence. Head Hght gray with 

 a distinct dark brown median vitta. 



Mesonotal prtescutuni dull brownish gray, the middle vitta 

 broadly divided l^y a dull gray median stripe which is much broader 

 than the brown margin enclosing it; lateral stripes rarely distinct; 

 scutum dull brownish gray, the lobes a little more brownish medially; 

 scutellum and postnotum yellowish gray with a narrow dark brown 

 median stripe. Pleura light gray, the dorsal pleurites more yellowish. 

 Halteres rather elongate, the stem somewhat pale, the knobs large, 

 dark brown. Legs with the coxae dull light yellow covered with a 

 sparse white pollen; trochanters dull yellow; femora dull yellowish 

 brown, the apices indistinctly darker brown; tibiae brown, darkened 

 at the apex; tarsi brown. Wings light gray; stigma distinct, dark 

 browTi; a pale vitreous band before the stigma, interrupted in the 

 vicinity of cross-vein r-m.; a vitreous spot beyond the stigma in cell 

 2nd Ri. Venation as in Plate XVII, fig. 18. 



Abdomen dull yellow, quite bright in places; a dorsal brown stripe 

 which is almost continuous, interrupted only by a narrow silvery 

 caudal margin to the individual segments; on the seventh to ninth 

 segments this band is in some specimens more broadened out to 

 cover the segment or nearly so; an interrupted brown stripe on the 

 sides of the tergites, this consisting of a large brown blotch about 

 midlength of each segment, on the seventh segment often becoming 

 confluent with the dorsal stripe; sternites dull yellow. Male geni- 

 talia (see Plate XVIII, fig. 39) with the ninth tergite (see Plate XIX, 

 fig. 56) small, subquadrate, much broader than long, the caudal 

 margin with a deep V-shaped notch whose edge is chitinized and 

 microscopically denticulate. Ninth pleurite incomplete, the pleural 

 suture very short, the pleural region cylindrical, produced caudad 

 and slightly entad as a long, slender lobe which is subspatulate ; 

 outer pleural appendage a very slender, elongate, cylindrical lobe, 

 pale, with scattered black hairs; this appendage is directed dorsad 

 with its tip close to the caudal margin of the ninth tergite; the 

 second appendage (see Plate XX, fig. 71) is flattened, deeply bilobed, 

 the outer lobe subcylindrical to somewhat flattened, chitinized 

 especially along the margin; the inner lobe is very extensive, flattened, 

 pale, with a somewhat blunt point directed laterad, the tip of the 

 lobe with numerous hairs; third pleural appendage consisting of a 

 compressed, flattened lobe, directed cephalad and dorsad, the apex 

 strongly chitinized, black, divided into two lobules by a deep notch; 

 the upper lobule cylindrical, smooth, the lower lobule with a few 



