1895. PEOCEEDIXGS OF THE NATIONAL MUSEUM. 415 



64. Fourth veiu reaches half way from dieoal cell to the wing margin, wings 



whitish, eyes narrowlj' separated umhilicala. 



P^urth vein reaches less than halfway from discal cell to the wing margin, 



wings hyaline but not whitish, whole of costal vein brown soccata. 



Fourth vein reaches three-fourths the distance from discal cell to the wing 



margin, wings whitish, eyes contiguous m«?ica (p. 427). 



65. With a black dot at tip of fourth veiu 66 



Without such a dot; fourth veiu reaches three-fourths the distance from 



discal cell to the wing margin manca (p. 427). 



6G. Fourth vein reaches only one-fourth the distance from discal cell to the 



wing margin, the black dot at its ti j) small umhiUcaia. 



Fourth vein longer, the dot larger ! tmbnaculata. 



67. Males 68 



Females 82 



68. Eyes contiguous or nearly .so 69 



Eyes distinctly separated, pile of abdomen yellowish 79 



69. Filament of hypopygium hidden 70 



Filament of hypopygium not wholly hidden 71 



70. Front tibia) dilated and thickly pilose on inner side; length, 6 mm. uhd'ita (p. 430). 

 Frouttibia) not dilated, pile on inner sidevery short; scutellum bearing about 



fourteen bristles; inhabits California; length, 10 mm. scuteUaris {]iA2Q). 



71. Hind legs destitute of processes 73 



Hind femora near apes on under side, and hind tibia) near base, bearing a 



rounded process ; length, 4 mm 72 



72. Process on hind femora situated at extreme apex of the femur and opposite 



a hollow in the hind tibia valga (p. 428). 



Process situated before the apex, and iu front of the hollow in the hind 



tibia hasalis (p. 410). 



73. Filament of hyj)opygium not fiexuous 74 



Filament very flesuous toward apes, not suddenly thickened at base, abdo- 

 men shining ; length, 6 mm flexuosa (p. 433). 



74. Base of filament of hypopygium very thick, then suddenlj- attenuated 75 



Base of filament not thickened 76 



75. Pile of thorax, abdomen, and legs yellowish, filament of hypopygium nearly 



twice as long as the hind femora; length, 4 mm inUgtronis (p. 432). 



Pile of thorax, abdomen, and legs black, abdomen white pollinose; upper 

 lamelhe of hypopygium acute, median ones larger, obtuse; length, 

 3 mm leucopiera. 



76. Palpi black 77 



Palpi yellow, under side of seventh abdominal segment jirolonged forward in 



two short processes; abdomen opaque, its pile yellowish ; filament of 



hypopygium thick, hidden at the tip ; length, 5 mm vara. 



11. Length, 3 mm. ; Eastern species 78 



Length, 9 mm. ; abdomen shining, its pile black; California species 



fimhriata (p. 429). 



78. Thorax opaque, filament of hypopygium very slender priapuJus. 



Thorax subshining, filament rather thick ; on each side of lower portion of 



hypopygium a shining, forwardly directed process; scutellum bear- 

 ing four bristles, hind metatarsi twice as thick as the others exigua. 



79. Filament of hypopygium free, slender, proboscis scarcely longer than height 



of head 80 



Filament hidden, intercalary vein not united with the fourth veiu, penul- 

 timate section of fifth vein much longer than the ultimate section ; 

 first joint of middle tarsi slender, much longer than the second; 

 length, 4 mm sordMa. 



80. Intercalary vein not united with the fourth 81 



Intercalary vein at base united with the fourth vein; length, 4 mm. .conjuncta. 



