ART. 9 AMERICAN XYLOTINE SYEPHID-FLIES SHANNON 35 



large triangular spots, the apices obtuse and directed inwards ; third 

 with rather obscured yellow^ish spots; fourth tergite dark metallic 

 green with mostly yellowish pile, black medianly and posteriorly; 

 discal cross vein joir.ing discai cell a little beyond middle; posterior 

 cross vein a little longer than section of fourth vein above it; squamae 

 white, faintly tinted with yellow; halteres yellow. Length 11.5 mm., 

 wing 9.5 mm. 



Tyfe locality. — Mount Rainier, above Longmire's, 5,000 feet, 

 Washington. 



Type.—Cvit. No. 27314, U.S.N.M. 



Holotype male; paratype male. 



This species is closest to iiavifrons. Besides the presence of the 

 yellow abdominal spots and difference in position of discal cross- 

 vein it diifers further by having the forceps in the male much less 

 curved and stouter. 



Distribution. — Washington, Mount Rainier, above Longmire's, 

 5,000 feet, August 3, 1905 (J. M. Aldrich). 



XYLOTA FLAVIFRONS Walker 



Xylota communis Walker. (In British Museum.) 



Xylota obscura Loew. (Iu Museum of Comparative Zoology.) 



Male. — Ocelli less than their altitude from hind-eye margins; 

 frontal triangle pollinose, except anterior margin; antennae brown, 

 third joint more yellowish, as broad as long, rounded apically ; arista 

 dark brown, distinctly shorter than width of face; mesonotum with 

 dark aeneous blue reflection, pile pale anteriorly, dark posteriorly 

 with fairly dense and long hairs; pleural pile pale; fore basitarsus 

 without long pale hair; ventral basal spines present; spur small; 

 second and third tergites opaque black, each with a pair of large 

 metallic bluish-green triangular spots with their apices directed in- 

 wards; fourth tergite dark metallic bluish-green; opaque regions of 

 abdomen with dark pile, metallic areas with pale yellow pile; discal 

 cross vein joining discal cell well beyond middle ; posterior cross vein 

 distinctly longer than section of fourth vein above it; wings smoky; 

 squamae white, halteres pale yellow. Forceps of usual type, dark 

 brown, a little swollen basally, strongly curved and tapering out- 

 wardly, apex obtuse. Length, 11.5-13 mm.; wing, 9-9.5 mm. 



Female. — Similar to male. Front moderately narrowed, black, 

 very lightly pollinose on upper half, broadly silvery pollinose on 

 lower except immediately above antennae; antennae reddish brown, 

 third joint slightly longer than broad ; arista black, distinctly shorter 

 than width of face; face very moderately excavated, coated with 

 grayish pollen; a whitish pollinose spot on inner side of humerus. 



