24 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lis 



Glyphipterygidae to Stenomidae after a careful study of their struc- 

 tures. He also indicated that on the basis of the genitalia, the Sten- 

 omidae and Xylorcytidae should be recognized as separate families. 



The failure of other workers to accept the evidence available from 

 studies of the genitalia led to controversy and confusion. Meyrick 

 admitted the value of the genitalia as an aid to classification but 

 based his higher categories primarily on wing venation and other 

 characters. 



Although the author is convinced that the genitalia are of primary 

 importance in the problems of delimiting higher categories in the 

 Stenomidae, an attempt to solve these problems without first making 

 a detailed study of the Central and South American species would be 

 unrealistic. A generic classification of stenomids is being undertaken 

 presently as a separate study. 



The following classification uses structures of both male and female 

 genitalia, as well as color and other adult characteristics. Illustra- 

 tions of the genitalia of both sexes are given for each species. The 

 terminology used for structures of the male and female genitalia of 

 Lepidoptera is very extensive and complex. Despite this, there is a 

 constant application of new names, as well as misapplication of old 

 ones, by taxonomists who need names for many structures with doubt- 

 ful homologies. Some workers apply the same name to structures 

 similar in appearance, even in widely separated families, while others 

 hesitate to apply the same name to two structures unless these have 

 been shown to be strictly homologous. The majority of workers do 

 not wish to contribute to further instability of nomenclature but are 

 unable to await the results of morphological studies dealing with the 

 homologies. The nomenclature of the genitalia in this paper follows 

 the recommendations made by EHots in Tuxen's publication (1956) 

 on insect genitalia. 



Biological studies and larval host plant records for North American 

 stenomids are few; known records for each species are listed in the 

 text. The larvae of the North American species feed chiefly on 

 trees and shrubs such as oak, maple, and laurel, although one species, 

 Stenoma mistrella Busck, has been found on timothy (Phleum pratense 

 L.). Exotic species are known to feed on avocado, custard apple 

 (Annona sp.), coffee, and cacao. 



The literature on the North American species of Stenomidae is 

 somewhat confused because of the uncertainty of many authors as 

 to the relationship of Stenomidae to other closely related families. 

 Much of this uncertainty has come from Edward Meyrick's work 

 (1880, 1889, 1890, 1913, 1915, 1922, 1925, 1928, 1929) in the Ste- 

 nomidae and related groups. 



