48 



7. Apical three or four segments of fore tarsi black; infuscation of wings 



confined to apical half or less of wing pictipes Zetterstedt. 



Fore tarsi entirely yellow 8. 



8. Thorax shining rufous, with slight gray pruinescence, lateral margins 



white, the dorsum with two submedian black vittae. . ruficollis Meigen. 

 Thoracic dorsum black, with dense gray pruinescence, not vittate 9. 



9. Infuscation of wing extending from apex of first vein to apex of wing 



geomyzina Fallen. 



Infuscation of wing confined to apical half or less . . . apicalis Zetterstedt. 



10. Dorsum of thorax shining rufous, without gray pruinescence 11. 



Dorsum of thorax black, with dense gray pruinescence 14. 



11. Each orbit with two bristles, the upper one absent; dorsum of thorax 



not vittate, the sides narrowly white duplicata, sp. n. 



Each orbit with three bristles, the upper one weak 12. 



12. Fore tarsi black pictipes Zetterstedt. 



Fore tarsi yellow 13. 



13. Thoracic dorsum not vittate melanostoma Loew. 



Thoracic dorsum with two black vittae posteriorly .... ruficollis Meigen. 



14. Infuscation of wing extending from apex of first vein to apex of wing. . 



geomyzina Fallen. 



Infuscation of wing confined to apical half or less . . . apicalis Zetterstedt. 



15. Thorax with two pairs of strong postsutural dorso-centrals, no presutural 



dorso-central present; upper orbital bristle present, of moderate length; 

 palpi of female yellow; infuscation of wing extending from apex of 



first vein to apex of wing; fore tarsi fuscous orbitalis, sp. n. 



Thorax with three pairs of strong dorso-centrals, the anterior pair in 

 front of suture; upper orbital bristle absent; infuscation of wing in 

 the form of two large clouds, one over the cross-veins and the other 

 on apical half; basal segment of fore tarsi in female deep black; in 

 male the basal or basal and second segments infuscated, remainder 

 white 16. 



16. Palpi yellow; third segment almost entirely yellow 17. 



Palpi and third antennal segment largely or entirely black 18. 



17. Thoracic dorsum black; basal segment of fore tarsi black, second segment 



faintly browned at base in male; fore femur yellow; hypopygial claspers 



long, drawn out into a long narrow strap-like tip apiculata, sp. n. 



Thoracic dorsum yellowish brown, with two or four darker vittae, the 

 lateral margins white; male with basal and second segments of fore 

 tarsi fuscous; fore femur with a dark-brown mark at apex on anterior 

 side; hypopygial claspers short, rounded apically. . . .johnsoni, sp. n. 



18. A large mark on anterior side of fore femur near apex; the fore tibia, and 



basal two segments of fore tarsus black nigripalpis, sp. n.<^. 



Fore tibia fuscous, basal segment of fore tarsus black . nigripalpis, sp. n. 9 ? 



Clusiodes americana, sp. n. 



Male and female. — Very similar to albimana, differing as 

 stated in the key, and in having the first posterior cell on wing 

 more narrowed apically, as well as in being slightly smaller. 



Length, 4 mm. 



Type, male, and allotype, Beltsville, Maryland, May 21, 1922 

 (J. R. Malloch). Paratypes, females, Mt. Cadillac, Mt. Desert, 

 Maine, July 25, 1919; Mt, Ascutney, Vermont, July 11, 1908 

 (C. W. Johnson); and Intervale, New Hampshire, August 23 

 (G. M. Allen). 



