l',U4.| NATIHAI, S(1ENLE8 OF lMllLM)Kl.rHl A. <)()1 



1. Cell .1/. iilwcnt -• 

 Cell -U, present •>• 



2. Haltercs with the knob darkened: antenna' of the male much 



loniicr than the tliorax (eiustern United States) ciicvra O. S.'" 

 Halteres pale; antenmp of the male short (eastern United States), 



rirukiris O. S." 



3. Cell 1st il/s present; body-coloration yellowish (eastern United 



States) pallida sp. n. 



Cell 1st Mi absent; body-coloration graj-ish 4. 



4. Size large (length of female 9 mm.) (western United States), 



argentea Doane'^ 

 Size smair(lengtii of the female ti mm.) (eastern United States), 



noreboracensis sp. n. 



Cliuus RHAPHIDOLABIS Ostcn Sacken. 

 isii<). RhaiMdulabis Osten Sackeu; Mon. Dipt. N. -Vm., vol. 4, p. l.'S4. 

 Rhaphidolabis polymeroides sp. n. 



Antennaj elongated, much longer than the head and thorax to- 

 gether, the segments of the fiagellum with abmulant outstretched 

 hairs; wings with a brown suffusion. 



Male, length about 6-6.5 mm.; wing, 7.1 mm. 



Rostrum brown, palpi dark brownish black. Antenna" elongated, 

 if bent backward they would extend to the middle of the abdomen; 

 flagellar segments very long, cylindrical, with abundant outstretched 

 hairs. Head gray. 



Thoracic dorsum brown with tln-ee dark brown stripes, the median 

 one longest and broadest, the lateral stripes short, narrowed in 

 front, broader behind; scutum with the lobes dark l)ro\\ni these being 

 continuations of the lateral prtescutal .stripes; .scutellum and post- 

 notum brown with a sparse gray bloom. Pleura? brownish 

 gray. Halteres long, pale at the extreme base, knob dark brown. 

 Legs, coxaj brown, more yellowish at the tips, trochanters yellow, 

 femora yellow darkening into brown beyond the base, tibia; and 

 tarsi brown. Wings with a dark brown suffusion, stigma indistinct, 

 veins dark lirown with conspicuous hairs; venation (PI. XXVII, 

 fig. 30). 



Abdominal tergiles dark brown, the hypupygium lighter brown; 

 sternites more yellowish. 



Holotype, d', Eureka, Cal., May 22, 1903 (H. S. Barber). 



This insect is coaspicuously different from any of the described 



•eucera Osten Sacken; Mon. Dipt. X. Am., vol. 4, pp. 281, 2S2; 1869. 

 'rivularis Osten Sackon; Proc. Acad. Nat. Sci. Phila., p. 249, pi. 2, fig. 16; ISi 

 ^argenlea Doane; Jouni. N. Y. Ent. Soc, vol. S, p. 190, pi. S, fig. 19; 1900. 



