192 
A. W. LINDSEY 
KEY TO THE NORTH AMERICAN GENERA 
OF PTEROPHORIDAE 
1. Wings entire ....^.Agdistis 
Wings cleft 2 
2. Radius of primaries with four branches or less 3 
Radius of primaries with five branches 10 
3. Primaries with only one or two veins in second lobe, anals ex- 
cepted; deeply cleft, with slender lobes 4 
With Ms, Cui and Cus all present 5 
4. Two or three branches of radius present .....Trichoptilus 
Only one radial .....Aciptilia 
5. Primaries with all branches of radius free Oidaematophorus 
Some branches stalked 6 
6. With a free vein (Rs) behind the stalked branches of the radius, 
ending behind apex of first lobe 7 
The last branches of the radius stalked Pselnophorus 
7. Secondaries with a tuft of black scales near tip of third 
feather Pterophoms 
No such tuft 8 
8. Second lobe of secondaries with two veins Adaina 
With three veins 9 
9. Fringes of inner margin of third lobe of secondaries with a few 
scales, sometimes faint in our species Exelastis 
Without such scales Marasmarcha 
10. Ro, Rs and Ri stalked Pterophorus 
Ra and Ri alone stalked 11 
11. Secondaries usually with black scales in fringes of inner margin. 
Anal angles of both lobes of primaries usually prominent Platyptilia 
Without black scales. Anal angles present but retreating Stenoptilia 
PLATE XX 
Neuration of Pterophoridae. 
1. Trichoptilus lohidactylus Fitch. 
2. Pterophorus peris celidactykis Fitch. 
3. Platyptilia carduidactyla Riley, 
4. Pselnophorus belfragei Fish. 
5. Adaina zephyria B. <& L. 
6. Aciptilia walsinghami Fern. 
7. Oidaematophorus lithodactylus Tr. 
(Genotype, European) 
8. Marasmarcha pumilio Zell. 
8a. Exelastis cervinicolor B. & McD. 
(First lobe of primary) 
9. Stenoptilia pterodactyla lArm. (Genotype). 
10. Agdistis americana B. & L. 
