TRICHOPTILUS PYGMAEUS 
191 
not be satisfactorily interpreted without studies of the trachea- 
tion of pupal wings. The single vein in the first lobe of the pri- 
maries of this genus may be II 2 + 3 + 4 J with independently lost, 
or R 3+4 with both and Rg independently lost. 
This interpretation of neuration together with the characters 
found in other parts of the body modifies the writer's former 
opinions of the phylogeny of the North American genera as ex- 
pressed in the Pterophoridae of America (Diagram, p. 286). In 
addition to actual differences between existing genera, it now 
seems unlikely that so many of these genera represent the an- 
cestry of others. Rather than this, they seem to be derived from 
com.mon ancestors in most cases. The following diagram ex- 
presses the writer's modified view of the phylogeny of our genera. 
ACIPTILIA 
TRICHOPTILUS 
PTEROPHORUS 
PLATYPTILIA 
EXELASTIS 
ADAINA 
PSELNOPHORUS 
OIDAEMATOPHORUS 
MARASMARCHA 
STENOPTILIA 
AGDIS^nS 
In order to correct the inaccuracies which crept into the key 
to North American genera in the Pterophoridae of America, the 
following key has been prepared. It has been found impossible 
to construct a key without falling back on neuration at some 
point, therefore it has been used freely to produce an accurate 
key. The wings may easily be examined as transparent objects 
without denuding or bleaching if they are mounted in pure al- 
cohol on a microscope slide, and all veins and thickened lines then 
become visible. 
