14 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.68 



In Professor Hine's collection: Kaslo, Britisli Columbia (Os- 

 born) ; Aniidon, Slope County, North Dakota, and Stump Lake, 

 Nelson County, North Dakota (Hubbell). 



CYLINDROMYIA ARGENTEA Townsend 



(Figs. 3, 27) 

 Ocyptcra argentea Townsend, Proc. Ent. Soe. Wash., vol. 2. IS'Jl, 144. 



As this species was misidentified by Coquillett in his Revision, 

 1897 (p. 86), and other writers followed him, thei-e are several 

 erroneous references in the literature, now belonging to nigra, new 

 species. Townsend in his original description mentioned three males 

 from District of Columbia and a female from Iowa. I examined 

 the three male types at the University of Kansas; the female was 

 not there. Two of the males are the species herein described: the 

 other is euchenor Walker. As I spread the genitalia, and the char- 

 acters are very distinct, there is no doubt whatever .ibout this con- 

 clusion. I restrict the species by excluding eurhenor. The two 

 species are the largest and most robust of the genus in the nearctic 

 region, as far as knowm. 



The species agrees in size and most characters remarkably with 

 hrassicaria, but has a wider and darker abdomen. The red on the 

 sides of tlie abdomen is not sharply defined, and the broad, change- 

 able and rather vague white or silvery pruinosity helps to conceal 

 the change of ground color. In most of the specimens of both sexes 

 the fourth principal segment bears only two pairs of marginal 

 biistles, although in some cases ther.' are three. This seems to be 

 a very good character for separating the females from related species. 

 There is usually a distinct third sternopleural briscle below the 

 anterior. The parafacial is considerably wider than the widest 

 portion of the third antennal joint. The face has a considerable kesi 

 above and is decidedly concave in profile on the lo ver part. The 

 fifth sternite has only a shallow median excision, the two sides of 

 which bear erect spiny hairs in a minute comb beginning a little 

 distance from the middle. The posterior forceps are long, united 

 to tip, very soft in structure, pale yellow or Avhitish in color, with a 

 considerable enlargement at the base, suddenly diminishing at middle. 

 The tip is closely applied as usual to the anterior forceps, reaching 

 almost to their extremity. The anterior forceps are shining black, 

 grooved at the bend, and curved forward somewhat irreguhirly from 

 near the base with a rather blunt point, which seems variable as in 

 other grooved forms from becoming a little twisted in drying. We 

 have no other species at all close to this. The last genital segment 

 of the female is globose, with the usual two sj'mmetrical hooks 



