THE CANADIAN ENTOMOLOGIST. 



for his species, the genera Lit/iomia, Ca/ocampa, Lithophane, Hadena, 

 Xyiena, Adinoiia, Dipterygia, Chariclea, Calopkasia, Asteroscopus, 

 Scotochrosta, and yet others are now used. Unfortunately the generic 

 title, becoming altered in spelling to Xyli/ia, has been retained for the 

 Lithophanoid forms, instead of the Hadenoid form, for which it was 

 intended and to which it properly belongs, 'i'his mistake I set right in 

 1876 ; I show that Xylophasia is a synonym of Xyiena, and that for the 

 genus Xylina of authors the name Lithophane (1816) must be used. 

 Only through such researches can we arrive at the certain titles of our 

 genera, and if we would one day reach a stable nomenclature, if our aim 

 is fixity and not laxity, the result of such studies must be adopted and 

 held fast. 



The type of each genus in the IVoctuidcc should clearly be first posi- 

 tively ascertained, and the structural features of such type fully exposed. 

 By comparison we can then group around such types the other species. 

 We can ascertain the reasonable limits of the, genera, weigh the characters 

 of outlying forms which obscure these limits, and, through comparative 

 studies in all stages, arrive at that condition of affairs in classification 

 where a certain generic term covers a certain total structure, and its use 

 calls up a picture of the greatest number of ascertained facts. The time 

 will then come when the present personal, opinionative use of generic 

 terms will give way to the scientific, impersonal one, when authority will 

 no longer usurp the place of reason and research. 



Acting again unfavourably upon the attainment of such a state of affairs 

 in literature and conversation, is the tendency to make a difference, 

 where in reality none exists, between authors as to the validity of their 

 names arising from the alleged want of technical completion of publica- 

 tion. I am here concerned only with generic titles. I hope to show 

 elsewhere that specific titles owe their recognition to a correspondence 

 between the object and the published description, and that, where the 

 supposed "type" of the original describer contradicts at all essentially the 

 original text, the "type" must be considered spurious, since the reason for 

 the name is to be found in literature, not in a labelled specimen. In 

 generic titles we are, however, solely concerned with literature, because 

 generic titles deal almost exclusively with already described species as a 

 matter of fact. New genera, based only on new species, depend also 

 largely upon the proper identification of the species, but these instances 

 do not affect the older generic titles and play no part in our present 

 investigations. 



