18 U.S. NATIONAL MUSEUM BULLETIN 244 



considered supplementary to the accepted criteria for specific classi- 

 fication and not a comparable substitute. It is the present author's 

 conviction that, because of the various complications involved, the 

 erection of new species for this family should not be based primarily 

 on the female stages. If a species is so uncommon that adult males 

 cannot be obtained easily, it is far better to leave the insect unnamed 

 until that stage can be collected and studied. 



Larval case. — For some time, the familiar bags which the larvae 

 construct have attracted considerable attention from various natural- 

 ists. This has been unfortunate as some workers have described new 

 species solely from such artifacts. To a large extent this incorrect pro- 

 cedure has resulted from the comparative rarity of the adult male and 

 from the misconception that the architecture of the case inevitably 

 was diagnostic. It is now realized by most workers that the superficial 

 appearance of the bags may vary considerably, depending upon the 

 host to which a particular larva restricts itself. The basic construc- 

 tion, moreover, is not influenced by such variation, but it may be 

 identical, or nearly so, for some related species. Thus, if used with 

 discretion, the structure of the larval case on occasion may have 

 specific value, but less frequently, generic. 



Classification 



Because a revision of the new world Psychidae necessarily involves 

 a study of the most specialized members of the family, a study of this 

 type can offer little toward an understanding of the classification and 

 phylogeny of the group as a whole. Several old world genera, includ- 

 ing some of the most primitive forms of the famUy, were examined 

 during the preparation of this work. The results are as yet inconclu- 

 sive and will be discussed more fully in subsequent papers. The 

 writer's intention is eventually to revise the North American 

 Tineidae and, through such a study and a more complete review of 

 the old world annectant groups, to arrive perhaps at a more natural 

 classification for the several families of Tineoidea. 



The precise limits of this "family" have not as yet been ascertained. 

 The examinations of several authors in the higher relationships of 

 the bagworms have been so superficial that diverse opinions concern- 

 ing the classification have arisen. The majority of these earlier 

 concepts were reviewed adequately by Tutt (1900, pp. 117-127). 



The Psychidae frequently are divided into two groups: the Micro - 

 Psychina and the Macro-Psychina. Several characters, involving 

 both morphology and behavior, serve to separate the two groups 

 (Ford, 1945). Intermediate conditions for some of these characters 

 exist, however, as both Tutt and Ford have pointed out; thus, the 

 division is not sharply defined, but it does serve to emphasize certain 



