BAGWORM MOTHS OF THE WESTERN HEMISPHERE 15 



Palpi: For our New World psychids, these structures offer limited 

 use in classification, owing to their extreme reduction in nearly all the 

 species. Only in the more primitive genera (Epichnopterix or below) 

 do they retain an observable size; they may be of generic value, if not 

 of specific importance, in these groups. 



Thorax: As previously mentioned, this region of the body may 

 bear taxonomically important characters, usually as observed in the 

 varying proportions and outlines of the lateral sclerites. This feature 

 has not been fully evaluated in the present study. Dissections 

 representing foiu- genera (viz, Astala, Cryptothelea, Oiketicus, and 

 Thyridopteryx) were examined. Relatively minor differences were 

 noted between the subalar sclerites of the mesothorax, but some of 

 this may be due in part to intraspecific variation. A thorough study 

 of the thorax in this regard eventually should be performed. 



Wings: Very little divergence exists in the wing color of most 

 species of psychids. Few genera throughout the world demonstrate 

 a distinct color pattern, and in the Western Hemisphere this charac- 

 teristic is restricted primarily to Oiketicus. Normal variation in the 

 color tone of certain members of this genus (e.g., 0. kirhyi) has re- 

 sulted in a rash of superfluous names. 



Of more importance than the actual wing color is the shape of the 

 wing scales and their distribution over the wing membrane. The 

 shape of the scale varies according to its relative location on the wing. 

 Those near the wing base usually tend to be the broadest and possess 

 the greatest number of apical teeth (if any) ; a gradual narrowing of 

 the scales is evident toward the outer margin. Consequently, it is 

 both necessary and convenient to select a particular area of the wing 

 to compare and discuss. In this study the discal cell of the forewing 

 was chosen. 



The wing venation is sometimes exceedingly variable in this family; 

 however, it is believed by the present author that for many species 

 this feature has been greatly overemphasized. Most of the variation 

 that is observed usually involves the medial veins. Only occasionally 

 is the radial system also affected. The exact cause of this inconsist- 

 ency is not definitely known, but perhaps it is caused by unusual 

 environmental influences on the larva and/or pupa. In some instances, 

 the variation that is observed may result, in part at least, from the 

 rearing of certain species. A study of the importance that rearing 

 may exert, however, has not been pursued. Only certain species 

 exhibit pronounced variation; others demonstrate a remarkably con- 

 stant venation. A very consistent pattern can be observed in Oiketi- 

 cus kirhyi. The wing veins of 65 specimens (130 wing pairs) of this 

 species were examined, and only two minor variations from the norm 



