488 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 114 



As this investigation progressed, it became apparent that not only- 

 had few attempts been made to point out the relationships among 

 existing species, but that several entities previously treated as entirely 

 unrelated species were actually very closely related subspecific com- 

 ponents of a single complex species, and that other close relationships 

 indicating the presence of small but distinct species groups had appar- 

 ently passed unnoticed. 



It also became apparent that much of the synonymy created by 

 earlier workers was caused by three difficulties: (1) the placing of too 

 much emphasis upon the deceptively variable characters of size and 

 coloration; (2) the failure to utilize the excellent characters furnished 

 by the structures of the head and genitalia ; and, (3) the lack of famili- 

 arity with previously designated type specimens. 



The majority of synonyms referable to the North American Acro- 

 lophidae are confined to a relatively small number of species occumng 

 in the eastern United States. These old, widely distributed, and 

 abundant species not only are common in collections but also exhibit 

 considerable variation in size and coloration over their respective 

 geographical ranges. 



The present taxonomic framework of the Acrolophidae is based 

 almost exclusively upon the adult males and although this is not the 

 most desirable situation, it will undoubtedly remain the most accessi- 

 ble and practical approach to the classification of this group until 

 considerably more can be learned about the females and various 

 immature stages. Thus, the present revision is likewise based almost 

 entirely upon males, and all of the author's statements describing the 

 structures and relationships exhibited by the various species are refer- 

 able to the males of those species unless otherwise indicated. 



In the majority of collections, the females of most species of Acro- 

 lophidae are considerably rarer than the males. The female is un- 

 known in some species and it has been only tentatively associated with 

 the male in others. The females, in common with those of the great 

 majority of families of the Microlepidoptera, possess two sexual 

 openings, one for copulation and one for oviposition. 



To the writer's knowledge, no acrolophid has ever been collected in 

 Canada. Nevertheless, a few of our more northern species, such as 

 morus, undoubtedly occur at least sparingly in southern Ontario. 

 There is also a noteworthy lack of records of acrolophids from the 

 northwestern portions of the United States. The group becomes 

 progressively more abundant both in species and individuals toward 

 the southern, and especially toward the southwestern, borders of the 

 United States. More species have been reported from Florida than 

 from any of the other eastern States. Many species have been record- 

 ed from Texas and a somewhat lesser number from its neighbor, New 



