I'UNGUS GNATS OF NORTH AMERICA'. 279 



dd. Knob of halteres blackish. 



e. Brown spot on wing at origin of the crossvein; proximal 



abdominal segments yellow anteriorly; pleura yellow 



anteriorly. St. Vincfent Isl. 5- nitens. 



ee. No brown spot at origin of the crossvein ; proximal 



abdominal segments wholly black ; Eastern U. S. 



6. veiitralis. ^ 

 aa. Thorax largely yellow, or if not then at least distinctly yellow be- 

 tween the dorsal vittae. 

 b. Mesonotum shining black except humeri and two slender con- 

 verging yellow lines on each side of a wedge-shaped black 

 median vitta. 

 c. Venter yellow, dorsum mainly black. 7. cuneola. 



cc. Abdomen almost wholly black ; female ; Mexico. 8. ainabilis. 

 bb. Mesonotum not so marked. 



c. Thorax with 3 distinct dark l)Town, longitudinal vitt?e, middle 

 one sometimes divided ; wing with fasciae or spots. 

 d. A brown cloud near apex of wing distad of the preapical / 



fascia. 9. Winthemii. ^ 



dd. No cloud on wing distad of the preapical fascia. 



e. Hind coxae and femora yellow. lo. striata. 



ee. Hind coxae and femora largely black. 11. lineola. 



cc. Mesonotum spotless, or with only 3 reddish stripes, or with 

 black spots on each side at base of wing, 

 d. Without conspicuous black spot on each side at base of wing, 

 e. Wing unmarked, 

 f. Abdomen yellow. 12. unicolor. 



ff. Abdomen fasciate. 



g. Thorax with 3 reddish brown vittae; fore metatarsvis . 



shorter than the tibia. 13. plebeja n. sp. ^ 



gg. Thorax yellow ; fore metatarsus as long as the tibia. 



14. hyalina. 

 ee. Wing fasciate. 



f. Wing with brown spot at base of crossvein. 



g. Hairs of thorax yellow, setae darker ; species from 

 the United States, 

 h. Crossvein shorter or not longer than the apical 



part of Ri. 15. oblectabilis. ^ 



hh. Crossvein longer than apical part of Ri. 



15a. var. of oblectabilis. 

 gg. Hairs and thoracic setae black; species from West 

 Indies. 16. concinna. 



ff. Wing without brown spot at base of crossvein. 



17. dryas n. sp. 

 dd. Mesonotum yellow with shining black spot, large or small, 

 on each side in front of the base of the wing, 

 e. Wing unmarked, hyaline. 



f. Pleura and metanotum black. 8. amabilis. 



3 



