Il8 MAINE AGRICULTURAI, EXPERIMENT STATION. I912. 



bb. Ri ends about opposite the base of the fork of M. 2. cingulata. 

 aa. Medium or small species. 



b. Costa, radius, media except sometimes the petiole, and cubitus 

 of the wings distinctly though sparsely setose, 

 c. Ri ends noticeably proximad of the fork of M ; small species, 

 d. Petiole of the cubitus 1-8 as long as the basal section of 

 M (Fig. 219) ; clasper (Fig. 100) ; N. Y. 3 vicina n. sp. 

 dd. Petiole of the cubitus over half as long as the basal section 

 of M (Fig. 220) ; clasper (Fig. loi) ; Cal. 4. dives n. sp. 

 cc. Ri ends about opposite or distad of the base of the fork of 

 M ; species 2.5 mm. or more in length, 

 d. Petiole of the cubitus over 1-2 as long as the basal section 

 of M. • 

 e. Ri ends about opposite the forking of M (Fig. 221). 



5. futilis n. sp. 

 ee. Ri ends distad of the forking of M (Fig. 266). 



6. abdita n. sp. 



dd. Petiole of the cubitus less than 1-4 as long as the basal 



section of M. 



e. Humeri, pleura in part and hypopygium (Fig. 103) more 



or less yellow ; knob of halteres dark. 7. ochrolabis 



ee. Thorax and abdomen, black. 



f. Halteres and coxae yellow; claspers (Fig. 139). 



8. habilis n. sp. 

 ff. Halteres and coxas black; claspers (Fig. 104). 



9. sciophila 

 bb. Media and cubitus without setae. 



c. Ri ends distad, or opposite (not more than i-io of wing length 



proximad) of the base of the fork of M, and base of Rs 



at or proximad of a point midway between the humeral 



crossvein and the tip of Ri. 



d. Thorax yellowish to rufous, coxee and femora dull yellow, 



claspers large, triangular (Fig. iii), hind tarsus i-S 



shorter than tibia. 10. fulvicauda. 



dd. Thorax dusky, claspers of different structure. 



e. Rs ends proximad of the tip of M2; halteres dark. 



f. Flagellar joints scarcely longer than broad; clasper 

 with 2 median lobes (Fig. 109). 11. tridentata. 



ff. Intermediate flagellar joints over twice as long as 

 broad; clasper without median lobes (Fig. 105). 



12. munda n. sp. 

 ee. Rs and M2 end about equidistant from the base of the 

 wing, 

 f. Ri erds distad of the forking of M; halteres dark, 

 g. Mesal process of clasper robust (Fig. 106 m) ; wing 

 (Fig. 22s). 13. dux n. sp. 



gg. Mesal process of claspers slender (Fig. 107 m) ; 

 wing (Fig. 226). 14. imitans n. Sp. 



ff. Ri ends about opposite the forking of M. 



