50 THE CANADIAN ENTOMOLOGIST. 



from works in which they stand as bare names, undefined and unde- 

 scribed. 



3. In the Preface to the Historical Sketch we naturally look for a 

 statement of the plan upon which the author has worked, and the prin- 

 ciples on which he relies for the correct exposition of generic names. And 

 we read that he adopts in general — not the rules of the British Association 

 — but those principles regarding genera enunciated by Agassiz, and more 

 recently by Dr. Thorell in his work on European Spiders, " with such 

 exceptions and modificatio?is as are indicated in my Canons of Systematic 

 Nomenclature" (published in Am. Jl. Sci. and Arts, May, 1872). Agassiz 

 not being at hand, I turn to Thorell as quoted by Wallace, Anniv. Address, 

 p. 10, and read : 1. " There must be definition and description and publication. 

 A recognizable figure of a species is sufficient, but of a genus there must be a 

 description pointing out the generic characters." And Thorell adds: " A 

 new genus that has been distinguished merely by referring to some particular 

 species of an older genus as its type, without in any way indicating which of 



the CHARACTERISTICS OF THE SPECIES IS TO BE CONSIDERED AS THE MARK 

 OF THE NEW GENUS, NO ONE CAN BE LOOKED UPON AS BOUND TO ACKNOW- 

 LEDGE. Nevertheless, it appears to me advisable to do so if the species 

 referred to deviate in any generally known way from the typical species 

 of the old genus, and always if the new genus has been once received and 

 acknowledged." With the proposition laid down in the first part of this 

 clause I fully agree, and it is in accord with the Rule of the Br. Ass'n. 

 The last part is advisory, and taken with the other, means that while 

 Dr. Thorell would concede a standing to genera already adopted and in 

 use, he would require definition and description and publication in future, 

 and would permit no genus to be based on a mere reference to a type, 

 except in one extraordinary case, that of a well known variation from the 

 typical species of the old genus. This advisory clause expresses an 

 individual opinion and is propounded for the consideration of naturalists. 

 But were it a law, it would afford scanty support to these new Hiibnerian 

 genera. There is no evidence that in any one of those taken from the 

 Tentamen or from Franck's Catalogue, etc., the typical species designated 

 by the author of the Hist. Sketch differs in any generally known manner 

 from the remaining species of the old genus, and certainly these genera 

 have not been received and acknowledged. 



And what are the " exceptions and modifications " indicated in 

 Mr. Scudder's Canons ? Canon 3 reads : " The mere enumeration of its 



