iNSEcuTOR iNSCiTi^ me;nstruus 139 



15. Dorsum of thorax with well defined band of black pile (face 



sometimes without long hairs; see bare face section) (Ore- 

 gon, Washington) nigrovittata Lovett. 



Thorax without such band 16 



16. Face distinctly excavated between antennae and tubercle 17 



Face but slightly excavated 18 



17. Arista about as long as width of frons measured across base 



of antennae; face broader than one-third width of head 

 (Idaho, Washington, Oregon) . . .petulca Will, and hoodiana Bigot. 

 (Abdomen yellowish =: hoodiana- flaviabdominalis, n. var.) 

 Arista very long, exceeding width of frons ; face about one- 

 third width of head (Europe; reported from Alaska), 



variabilis Panz. 



18. Arista shorter than width of frons ; medium sized species 



(Alaska) yukonensis, n. sp. 



Arista slightly longer than width of frons ; robust species 



(pacifica and occidentalis complex) 19 



19. "Thickly white pilose species" (California) pacifica Hunter. 



Thorax with intermixed black and brownish pile (California, 



New Mexico, Colorado, Alaska) occidentalis Will. 



C H ILO SI A — F^ M ALES 



Byes hairy; antennal pits separated 



1. Face bare Subgenus Chilosia 2 



Face hairy Subgenus Chilomyia 17 



2. Frontal view of outline of head triangular shaped; posterior 



cross-vein longer than distance from its tip to tip of apical 



cross-vein. Large, usually very long pilose species , 3 



Frontal view of head broadly oval in outline; posterior cross- 

 vein shorter than distance from its tip to tip of apical cross- 

 vein ; short pilose species 8 



3. Shining bronze, with abundant golden pile (Aiexico), 



chrysochlamys Will. 

 Not shining bronze 4 



4. Abdomen shining steel blue; third and fourth segments with 



black pile (California, Washington) chalybescens Will. 



Abdomen blackish 5 



5. Arista distinctly shorter than width of frons measured across 



antennae ; pile rather short (Idaho) julietta. n. sp. 



Arista longer than width of frons 6 



6. Face, much produced downward, cone-like ; legs largely black 



with long pile (Oregon, Washington) ferruginea Lovett. 



Face rather moderately produced downward 7 



