246 GEORGE D. HULST. 



structure without tlie known existence of intermediate forms in 

 nature, to be the application of the rule. As a result some of his 

 genera cover almost subfamily differences, as witness such as Pseudo- 

 panthera and Crocota. All divisions are artificial in theory, and 

 accidental in fact, and it is more natural, and it seems to me more 

 scientific, while using discretion, to consider wide variations in 

 structure as valid bases for genera even though intermediate forms 

 may exist which may be referred with equal propriety to one or to 

 the other. 



I have also given more importance to some details of structure 

 than is given by Mr. Meyrick. As an example, my own experience 

 leads me to regard the pencil found on the hind tibiae of the males 

 of many species as a thoroughly reliable point of structure. It may 

 often be rubbed off, and the groove in which it rests be difficult to 

 discern, but the structure is not variable in the same species. 



There are other structural peculiarities which may modify classifi- 

 cation in the future. Some of these may be found in the larval and 

 pupal stages, but, apart from what I have noted, nothing has as yet 

 been observed which seems reliable. A character in the imago which 

 may be of greater importance than I have given it, is the peculiar 

 form of the subcostal vein of hind wings near the base. Prof. 

 Comstock, who discovered this peculiarity, makes it of family im- 

 portance. My own observations lead me to believe it cannot be 

 considered exclusive. First, it is scarcely distinct in some of the 

 Sterrhinse, and is wanting in some that we must consider true Geom- 

 eters such as the genera Mccoceras, Melanchroia, etc., as well as some 

 genera of the Monocteniinae and Strophidiiuaj. On the other hand 

 the tendency to the basal angulation of the costal vein of the hind 

 wings seems to me to be as fully developed in some of the Geometri- 

 form Noctuina, as in the Sterrhiiuie and Monocteniinte, and much 

 more so than in some other genera. In some of the Catocalce this 

 angle is clear, though it is apt to be overlooked, as the vein is very 

 faint, while the vein, which would be vein 9, and which is coincident 

 with 8 just beyond base is very strong, and is ordinarily regarded 

 as the only one. 



Very considerable use may in the future be made of modifications 

 of the antennae, based on a form of structure, so far as I know, not 

 hitherto observed. In the species which have the antenuie bipecti- 

 nate in the males the position of the pectinations with regard to the 

 segments upon which they stand is very different. In a very few 



