AMERICAN LEPIDOPTERA. 209 



pletes the chain in one way to the lower forms. Equally close to Helio- 

 this though catalogued after Shinia comes Melaporphyria with its dark 

 colors and ovate eyes, leading readily to Melir.Uptria with abbreviate and 

 armed fore tibia : between Melicliptrio and Shinia. Heliophmw holds a 

 place, bridging the gap between the two through Pseudotamila with scab 

 vestiture and ovate eyes. Heliolonchc comes next, most nearly related 

 to Meh'cfifitria, followed by Axenust, which is naturally followed by 

 ■Seftaca, which in turn is very near Annaphi/a. Pseudacontta forms 

 the bridge between the pale more Trail forms of Shinia and the genus 

 which it mimics. Derrima is aberrant, having decided affinities with 

 Char idea peruana, and through it to Pluxia or allies. 



These relationships I have tried as far as possible to express by cata- 

 loguing — with what suceess my readers must say. 



In the course of my work also the question as to what use I should 

 make of Hubner's genera presented itself. I had already expressed 

 myself strongly in favor of entirely ignoring Hiibner, not having at that 

 time the experience with other authors that I have had since. I have 

 therefore re-examined the entire subject, have read all that is written 

 on it and have substantially adopted neither of the views heretofore 

 advocated, but have laid out a course, apt to prove repugnant to most, 

 but which I believe to be the one most consonant to justice and rea- 

 son. 



It has never been determined what is necessary to create a genus ; 

 what, if any. description was needed, and there have been as many 

 courses as there have been authors. In the earlier times generic ideas 

 were widely different from those now held, and characters universally in 

 use now were then unknown. 



Genera have been even in recent times created by a mere designation 

 of the type, and as Hubner's genera and many of Guenee's and Walk- 

 er's are so imperfectly described, that it is utterly impossible to recognize 

 the genus apart from a comparison with the species placed in it, they all 

 stand on about the same footing and deserve the same treatment. 



Generic ideas have, as before remarked, changed, and while Hiibner's 

 and Guenee's genera may have been perfectly />ure in the state of the 

 science at that time, they are now deemed heterogeneous. Yet it must 

 be remembered that all these authors had their own idea of what consti- 

 tuted a genus, and this idea can only be gathered from a study of all, the 

 species placed by them in tin' same genus. Unless a genus is expressly 

 limited by description sufficient to identify it, or unless there is one par- 

 ticular species distinctly designated as the type of the genus, every 



IKANS. AMEH. EST. SOC. X. (53) DECEMBER, 1882. 



