_ T 1 • 



%\\t Canadian JUtomoloflbt 



Vol. XXXIV. LONDON, AUGUST, 1902. No. 8 



WHAT IS A GENUS?* 



BY HENRY H. LYMAN, MONTREAL. 



This question is one that it is extremely difficult to answer satisfac- 

 torily. 



The great naturalist, Agassiz, in his Essay on Classification, wrote : 

 "Genera are most closely allied groups of animals differing * * * * 

 simply in the ultimate structural peculiarities of some of their parts." 



The Century Dictionary defines genus as " a classificatory group 

 ranking next above the species, containing a group of species (sometimes 

 a single species) possessing certain structural characters different from 

 those of any others." It goes on, however, to say : " The value assigned 

 to a genus is wholly arbitrary —that is, it is entirely a matter of opinion 

 or current usage what characters shall be considered generic and thus 

 constitute a genus ; and genera are constantly modified and shifted 

 by specialists, the tendency being mostly to restriction of genera, with 

 the constant multiplication of their numbers, and the coinage of new 

 generic names. A genus has no natural, much less necessary, definition, 

 its meaning being at best a matter of expert opinion ; and the same is true 

 of the species, family, order, class, etc.'' 



It will doubtless be readily granted, however much we may differ as 

 to generic values, that at least all the individuals of the same species 

 should belong to the same genus, but this, unfortunately, is not always 

 the case, as some species vary sufficiently in structure to run into two or 

 more genera, as these are frequently defined. 



Having had the good or bad fortune to find about the middle of 

 August, 1898. a mature larva closely resembling that of E. Oregotiensis, 

 though differing in colour, from which I bred on 1st of April, 1899, a 

 moth so closely resembling E. Eg/A that probably 99 men out of a 100 



*Reac! before the Montreal Branch, 13th May, 1902. 



tThe question whether the generic name Euch;etes, proposed by Harris, or 

 Euchxtias, proposed by me, should be used for the genus of which this moth is the 

 type, I am willing to leave to the principal authorities on such matters to decide, but 

 wish to say what I perhaps did not make sufficiently clear in my note on page 52 

 (correcting my error in regard to the name I proposed for a genus in the Coleoptera), 

 that in giving Mr. Henshaw's views upon the subject, as conveyed to me by letter, I did 

 not mean it to be inferred that I accepted or concurred in them. 



