40 NOTES ON MELANOSTOMA (dIPTERA; SYRPIIIDAE) 



Descril^ocl from twenty individuals from Alhaml)rft and B(M-k- 

 eley, California, 1919 and 1920. 



Female. Antennae brownish-blaek; tliird joint oval, twice a.s long as broad, 

 yellowish red below; arista dark brown, bare. Vertex shining bhiish-blaek, 

 pile black, above the antennae a band of gray pollen. Face on the sides below 

 grayish i)ollinose in obscure ri]i]^le-lik5 formation, a median shining bare 

 stripe not reaching the antennae. Cheeks shining gray w^th scant whitish 

 pollen and white pile; i)ile of the face white below, and black above, the 

 antennae. In profile the face is rostrate, the epistoma projecting beyond 

 the facial tubercle and this in turn projects beyond the antennal tubercle. 



Thorax and scutellum shining bluish-gray, pile white, a few longer black 

 hairs on the margin of the scutellum. Wings project slightly beyond the body, 

 hyaline; stigma light amber. Ilalteres gray. Tegulae white, fringe fulvous. 

 Legs black, apical half of the four anterior femora reddish-brown, hind knees 

 fuscous, anterior and middle tibiae reddish-brown, basal joints of the four 

 anterior tarsi yellowish brown; base and ai)ex of hind tibiae fuscous; pile of 

 the legs mostly white. 



First abdominal segment shining grayish-black. Second segment on tlie 

 sides and anterior margins shining grayish-black, posterior margins oi)a(iue 

 black; in the middle of the segments two bronze spots. Third segment opacjue 

 black, with two shining orange colored spots narrowly separated from the 

 anterior border. Fourth segment shining grayish with two similar orange 

 spots and with an interrupted ojiaque black band on the jjosterior half. Fifth 

 segment shining greenish-gray, the pile of the abdomen white, on the o))aque 

 areas black and white intermi.xed. Abdomen narrowly oval, widest at the apex 

 of the second segment. 



Length, 6 to 8.5 mm. 



Described from twelve individuals collected and Ijretl at 

 Alhaml)ra, California, 1919 and 1920. 



This appears to be the form described by Bigot as ilf . rostra- 

 tum~; it differs from typical ohscurum in the facial stripe being 

 narrower, the thorax more of a bluish-black instead of greenish- 

 black, the scutellar hairs longer and more black on the disc as 

 well as at the edge. 



This species is very abundant in Southern California in Spring. 



Melanostoma trichopus Thomson 



In th(> National Museum collection are several specimens 

 from Alaska which have been identified as this sjiecics. In the 

 facial characters, including rostrate eiiisioma, they closely re- 

 seml)l(> M. ohscurum Say and the variety /v».s7/7/////// liigol. The 

 abdomen of the male is narrower than in these tvvo Hies, while 



2 Bigot, Ann. Hoc. Ent. France, 1884, p. NO. 



