March, 1917.] FoRBES : HydRIOMENIN^ OF THE UnITED StATES. 47 



2. Hind tibia shorter, or with rudimentary spurs ; or vestiture overlaid with 



loose hair, or black and white CEnochrominae and Ennominae (2). 



3. Abdomen spined dorsally Phigalia in Ennominae. 



3. Abdomen not spined dorsally 4 



4. Front smooth, palpi short Paraptera in Hydriomeninae. 



4. Frontal tuft and palpi projecting beaklike. . .D/a,jn'c/i/!.y in Ennominae (i). 



5. M, (vein 5) of hind wings well developed, tubular 6 



5. M2 of hind wing rudimentary or absent 11 



6. M2 from decidedly above middle of cell in both wings ; our species with 



enlarged humeral angle, reduced or wanting frenulum ; almost always 

 green and always simply marked Geometrinae. 



6. M2 at least two thirds as far from top as from bottom of cell in at least 



one, and usually both wings 7 



7. Sc and R of hind wing fused near base for less than a quarter length of 



cell, or in contact and immediately and abruptly diverging 8 



7. Sc and A fusing for more than a quarter length of cell, or shortly near 



end of cell 9 



7. Sc and R entirely separate, connected by a distinct cross-vein, more than a 



third way out on cell a few Hydriomeninae. 



7. Sc and R separate but closely approximate for second fourth of cell, at 



least, the cross-vein if present obscure and located where Sc and R first 

 approach 10 



8. Frenulum absent, antennae clubbed Coronidiinae (3). 



8. Frenulum and antennae normal Sterrhinae (4) . 



9. Tongue well developed, one or two well marked accessory cells. 



Hydriomeninae. 

 9. Tongue rudimentary ; radial branches crowded toward origin, not enclosing 



a distinct accessory cell Alsophila in CEnochrominae (s). 



10. R4 of fore wing running to costa about 1/16 inch before apex, no accessory 

 cell; eyes and mouth-parts very small; very hairy; eyes oval . . Brephinae. 



10. R4 running to apex; or with normal accessory cell, vestiture, eyes, or palpi 



and tongue, eyes round CEnochrominse and Ennominae. 



1 1. Two large accessory cells in fore wing not connected to Sc. 



Grossbeckia in Hydriomeninae. 

 II. With one or no accessory cells, or with them rhomboidal and the first con- 

 nected to Sc most Ennominae, 



North American Genera of Brephin^. 

 M3 and Cui stalked, at least in hind wing; hind wing white. .Leucobrephos. 

 M3 arid Cui not stalked in hind wing; hind wing orange Brephos. 



North American Genera of Hydriomeninae: 



Males : 



I. Sc and R connected by a crossvein, Cuo extremely reduced in hind wing. .2 



I. Sc and R fused, at least toward end of cell 4 



