210 J. 1$. SMITH. 



species placed in it by its author must be considered as equally a type, 

 and the aggregation of these' species, distinct though they may be ac- 

 cording to our ideas, is the generic idea of the author as to that particu- 

 lar genus. When in the course of time the genus is divided up and 

 new genera are created, based on some of its species, the original generic 

 name, though it be retained, should not be credited to its originator, 

 because the genus so named in the sense of its author has ceased to 

 exist, and the genus should be credited to the author limiting and de- 

 scribing it. 



This idea I have followed throughout this paper, and shall continue 

 to follow it until it is shown to be incorrect or unjust, and ull the older 

 works are placed on the same basis. It is, however, perhaps necessary to 

 say that among Hubner's works entitled to consideration I do not count 

 the Tentamen. 



While writing this paper and in the course of my studies on the group 

 I have had before me, all the European genera and most of their species, 

 and I find that while it is a perfectly easy task to limit the European 

 genera, the American species, being much more numerous, so gradually 

 diverge that it is a matter of great difficulty to say exactly where the 

 line dividing the genera shall be drawn, and while I believe that the fol- 

 lowing synopsis is accurate and sufficient to define the genera as they are 

 now represented, I am well convinced that species will be found which 

 will eventually close the gap between Heliothix dipsaceus and Shinla 

 Thoreaui, and that all the species must be either placed in one genus, or 

 genera must be so multiplied that there will be only one or two species 

 in each — that is provided there be no new characters discovered upon 

 which genera can be based. 



Further and particular discussion as to structure will be more in place 

 when speaking of the respective genera. 



My thanks are due to Messrs. Henry Edwards and B. Neumoegen of 

 New York for the loan of their and many of Mr. Grote's types, and to 

 all my Brooklyn friends who placed at my disposal their entire collec- 

 tions in which (especially that of Mr. Tepper ) there were many of the 

 types. 



