224 Annals Entomological Society of America [Vol. X, 



Syrphus medius n. sp. 



Length, 10 mm. Face yellowish, yellowish pilose, with a distinct 

 blackish brown stripe in the middle, which begins at the oral margin, but 

 does not reach the antennae. Eyes bare. Antennae brown, third joint 

 lighter on the under side. Cheeks brownish black, separated from oral 

 margin by a yellowiih border completely cutting off the connection 

 between the black on both sides (as in S. americanus). Front brownish 

 yellow, with a slight greenish reflection, a darker median furcate line 

 ranning from the vertex to the base of the antennae, forming an inverted 

 Y; lighter on sides, with black pile, a shining black spot above each 

 antenna; vertex shining black, black pilose. Thorax bronze, shining, with 

 fine yellowish pile ; scutellum lighter, with the same colored pile ; abdomen 

 black, with three uninterrupted yellow cross-bands. The first abdom- 

 inal cross-band entire; anterior margin distinctly concave; posterior 

 margin gently sinuate, having a medial diameter of about one-half of 

 that of the distal ends. The anterior margin extends directly to lateral 

 margin of the body, while the posterior is cut obliquely a short distance 

 from the tip and reaches the lateral margin in half its width. The 

 bands of the second and third segments are equal in width throughout ; 

 both have a median anterior and posterior projection; attenuated at 

 the ends and reach the lateral margins in the same manner as the first 

 cross-band; fourth segment with a narrow yellow hind margin; fifth 

 segment yellow, with a narrow transverse blackish spot in its middle; 

 legs yellow, coxas black, hind femora with a distinct brownish ring on the 

 distal half, all tibiae and tarsi yellow. Wings hyaline, stigma yellowish. 



Habitat: Fort Collins, Colorado, one specimen. L. C. 

 Bragg, Collector, August 22, 1911. 



5. medius differs from 5. abbreviatiis in having the distinct 

 brown stripe in the face; the brownish spots above the antennae, 

 the cross-band on the second segment entire, the cross-band 

 of the third and fourth segments not all convex, sinuate, and 

 the black color of the cheeks separated on the under side of the 

 face by the yellow margin round the mouth. 



S. medius differs from 5. americanus chiefly in that the 

 three principal yellow cross-bands attain the lateral margins 

 of the abdomen. 



S5n'phus similis n. sp. 



Length, 12.5 mm. Eyes globose bare, face yellowish, with bluish 

 tinge, whitish poUinose and with sparse yellow pile; frontal triangle 

 whitish poUinose, with two shining black spots above antenna:; the pile, 

 and that of the vertex, black; vertex shining, metallic greenish; a brown- 

 ish median stripe from vertex to black spot above antenna^; occiput 

 broad, sides parallel, silvery poUinose, with rather abundant stubby, 

 whitish pile; antennae brownish, third joint oval, blackish at tip, with 

 brown base; cheeks broad, yellowish. Thorax a dull, slightly shining 

 black, with abundant light colored pile, and a bluish dorso-median 



