220 Annals Entomological Society of America [Vol. X, 



similar to the first, but nearer the anterior margin of the segment, and 

 considerably larger; segments four and five with a narrow, yellow, 

 posterior border. Legs black, with white pile, knees fuscous, hind 

 metatarsi only slightly or not at all thickened, tarsi with short, stiff, 

 yellow pile. Wings hyaline, stigma yellow. Male differs from female 

 in having the face with more of a bluish tinge; the cheeks are black and 

 the oral margin has a yellow spot on it. The scutellum is darker and 

 the pile is about twice the length of that of the female ; the first abdominal 

 spots are triangular and very small, and the fifth segment has no yellow 

 posterior margin. 



Two males, one female. C. S. Mead, collector, Cherokee 

 Park, 7600 ft., July 30, 1913. 



Melanostoma johnsoni n. sp. 



9 , 8 mm. Thorax blue or greenish metallic, head shining, bluish or 

 green. Face prominent with whitish pile and lightly dusted on the 

 sides with whitish pollen, tubercle and middle shining, a narrow trans- 

 verse pollinose stripe below the antennas which projects upward in the 

 middle between the antennas, front shining, lightly dusted on side with 

 whitish pollen, a shining spot immediately above and surrounding the 

 antennae, pile black. Vertex shining, black pile. Antennae elongate, 

 third joint as long as the two preceding joints, sub-quadrate viewed from 

 above, brownish, light-reddish underneath, arista brown, basal; occiput 

 whitish pollinose, with whitish pile. Thorax metallic dark blue, or green, 

 shining, with whitish pile. Scutellum of the same color as the thorax 

 with marginal pile longer than the rest. Abdomen ovate, shining, 

 brownish, with short white pile, which is longer on margin and near 

 the base, and three pairs of yellowish abdominal spots. Second segment 

 with two small oblique medial yellowish spots, segment three with two 

 similar spots, but larger and more ovate. Spots on segment four 

 similar in shape and size to the front pair. Legs testaceous, hind femora, 

 except at the base and the tip, part of the tibiae and the tarsus, fuscous, 

 hind metatarsi slightly thickened. Wings hyaline, stigma yellow. 



Habitat: Two females. S. A. Johnson, collector, Denver, 

 Colorado, April 4, 1902. 



Melanostoma monticola n. sp. 



Length, 9 , 7 to 9 mm. Face projecting, slightly excavated below 

 the antennae, whitish pollinose, with white pile, shining black; epistoma 

 projecting downward, tubercle prominent, a smaller one on oral margin ; 

 from tubercle up to the base of the antennae a slight median depression; 

 above the insertion of antennae two slightly raised, black, arcuate 

 ridges, meeting on the median line. Front shining metallic green, 

 whitish pollinose on sides, black pilose, and slightly depressed; vertex 

 shining metallic green, black pile; eyes converging at apex. Cheeks 

 black, white pilose. Antenna^ brownish, third joint reddish below, 

 sub-ovate; arista bare. Thorax shining metallic green, white pile. 

 Scutellum of the same color, pile short, a slight depression following 



