8 PROCEEDIISrGS OF THE NATIONAL MUSEUM vol.69 



readily separate this species from chinooh. The fourth and fifth 

 tergites are very extensively yellow. The even-sided abdominal mar- 

 gins distinguish it from integruin which has the apical corners of 

 the tergites produced. 



Length, 13-15 mm. 



Seven specimens, all males. 



The antennal joints are approxunately 1 : 1.5 : 2. The fore side 

 hind margins of the fifth tergite are about 4.5 : 1 : 2. 



Type locality. — El Paso County, Colo. 



Type. — In United States National Museum. 



Distribution. — Colorado: El Paso County, June 7 (Champlain), 



Locality and collector? Locality and collector (Coquillett collec- 

 tion). Montana: Locality? (Cornell University, lot 35, Willistoii 

 collection). Idaho: Locality? (Cornell University, lot 35, Williston 

 collection). 



CHRYSOTOXUM YPSILON Williston 



Clirysotoxmn ypsilon Williston, Synopsis N. A. Syrphidae, 1886, p. 14. — 

 CxjRRAN, Can. Ent., vol. 56, 1924, p. 39. 



Large species with the arista much^ shorter than antenna, in the 

 male the third joint as long as the basal ones combined, in the female 

 the third joint is much the longer; pteropleura with black pile; 

 anterior corners of abdomen mostly or entirely yellow pilose ; abdom- 

 inal bands broad and joining margins of tergites; lateral margins 

 beyond middle of second tergite yellow; apical corners of tergites 

 strongly projecting; second sternite with yellow post margin; ster- 

 nites 3 and 4 and in the female the fifth each with a pair of large 

 yellow spots ; Length, 15-18 mm. Two males, three females. 



Type locality. — New Mexico. 



Type. — In United States National Museum. 



Distribution. — New Mexico: Locality? (Williston collection) ; Pe- 

 cos, June 21 (W. P. Cockerell). Nevada: Ormsby County, July 6 

 (C. F. Baker). Colorado: Locality and collector? 



CHRYSOTOXUM AZTEC, new species 



Chrysotoxitm integrum Williston, Giglio Tos, Mem. K. Acad. Sci. Nat. 

 Torino, ser. 2, vol. 43, 1893, p. 10 ( misidentification ) . 



Male. — Frons black pilose; antenna! joints about 1:1:2.5; arista 

 much shorter than length of antenna; mesonotum blackish pilose; 

 pteropleura black pilose; base of abdomen mostly yellow pilose; 

 bases of femora black; abdominal bands rather broad, joining sides 

 of abdomen, which are yellow beyond middle of second tergite; 

 apical corners of tergites moderately i^rojecting; sternites yellow only 

 on hind margins. 



