287 



W'itliin the genera the difficuhies of the systematist multiply. 

 Many species are vei"y close, especially in Platyptilia, and can be sepa- 

 rated only by careful study. In this one genus the genitalia are of 

 no assistance, but in the others they are usually helpful. We have 

 come to the conclusion that one trouble in the past has been the failure 

 of the student to observe closely the more minute features of these 

 insects, and the placing of undue emphasis on the pattern of the wings. 

 In Oidacmatopliorus characters found in palpi and legs often serve to 

 separate closely related species, while we have found that the pattern 

 of the primaries is subject to such great variation that it is difficult 

 to point out single features for the separation of many species. The 

 remarkable fragility of specimens, once they have been dried, results 

 in many lacking parts which might place them readily. The only 

 remedy for this is, of course, careful collecting and abundant material. 

 It is hopeless, without an extensive knowledge of the family, to attempt 

 to identify many of the sad specimens which seem to be all too numer- 

 ous in collections. 



Too little work of a scientific nature has been done on the early 

 stages to enable us to make generalizations of value, so we refer our 

 readers to the notes given under various species. 



The larvae of some species bore in the stems of plants, but in 

 most of those whose habits are known they are external feeders on 

 leaves or flowers. The pupae are naked, attached to a button of silk 

 at the caudal end only. 



We have adapted a portion of the key to the genera given by 

 Meyrick in the Genera Insectorum to the uses of this paper, following 

 the Comstock-Needham nomenclature, and have drawn our notes on 

 genera largely from the same source. 



Key to the Genera 



1. Wings entire Agdistis 



Wings cleft, the primaries bifid, secondaries trind 2 



2. Primaries with vein R, absent 3 



Radius of primaries with all five branches 9 



3. Primaries with CUj absent (only two veins in second lobe), deeply cleft 



and with very slender lobes 4 



CUj present, primaries cleft much less than one-half their length 5 



4. Primaries with vein R^ present Trichoptilus 



Primaries without R^ Acintilia 



5. Branches of radius of primaries free Oidaematophorus 



Some branches of radius stalked 6 



