AMERICAN DIPTERA. 47 



46. Arctopliila flagraiis O.. Sack. 



Fort Collins, Colorado ^^ Gillette). One female, which measures 

 only 9 mm., I refer to this species. Only the male has been de- 

 scribed ; although the anterior cross-vein is situated well before the 

 middle of the discal cell, and there is such a difference in size, still 

 I am confident that the specimen must be referred here. The more 

 robust form and pilosity indicate its affinities with the groups having 

 the anterior cross- vein beyond or near the middle of the discal cell. 



It differs from Osten Sacken's description as follows : Female. — 

 Length 9 mm. ; third autennal joint more yellowish, the two basal 

 joints nearly black ; ground color of thoracic dorsum and scutellum, 

 seen through the yellowish pile, is metallic dark greenish, or greenish 

 black. The middle tarsi are quite uniformly blackish, not reddish 

 basally, like the hind tarsi. In all other respects it agrees closely 

 with the description. 



47. Eristali$$ seiieus Fabr. 



Washington, D. C. Three males taken May 2, August and No- 

 vember 28. Dixie Landing, Va., one female, July 13 ; agrees well 

 with descriptions. 



48. Eristalis n. sp. (V) aft', atrim.nnns Loew (uon Williston). 



Bath, Jamaica (E. M. Swainson). One female I doubtfully 

 identify as Loew's species ; and I feel assured that, the species from 

 Santo Domingo described by Williston in his monograph (pp. 173- 

 174) is not atrimanus Lw., but a new species, for which I j^i'opose 

 the name willistoni. 



The present specimen from Jamaica agrees well with Loew's de- 

 scrij)tion in all except one particular ; the anterior lateral spots of 

 third abdominal segment are not seneous, but yellow like the lateral 

 portions of second segment. The interrupted, shining, iBneous fascia 

 of fourth segment, when viewed in certain lights, shows its true 

 ground color to be yellow ; and it should also be noted that the yel- 

 \o\x of second segment is shining on anterior median margin. 

 Whether the markings of third segment vary in atrimanHa 9 from 

 shining seneous to more yellow cannot be known until more material 

 is obtained, and this only will decide the position of the present 

 specimen. The latter is just the size of Loew's specimen, about 

 9.1 mm., and possesses the oblique yellowish markings at base of 

 wings described by Loew as connected with the pre-sutural band. 

 Williston's specimens lack these, and are much larger, being 12 mm. 



TRANS. AM. ENT. SOC. XXII. MARCH, 1895. 



