150 



Notes on the Genus Triphsena, Och. 

 By R. Adkin, Esq. Read February 26th, 1891. 



Of the numerous genera comprised in the British Noctua; 

 perhaps none is more familiar to us than TriphcEna. The 

 wide geographical distribution of the six species contained in 

 it, their bright appearance, lively habits, and proneness to 

 aberration, rendering them particularly attractive even to the 

 most casual observer. The generic limit, moreover, appears 

 to be a very natural one, the species bearing a strong super- 

 ficial resemblance to each other, both in the larval and perfect 

 stages ; in the former their habits are also much alike, and in 

 the latter by no means dissimilar. 



It is true that many Continental authors ignore this generic 

 limitation, and prefer to include the six species in Ochsen- 

 heimer's greater, and, to my thinking, unwieldy, genus 

 Agrotis, and possibly other species occurring on the Continent, 

 but which are unknown to our fauna, may render its boundaries 

 less clearly defined, but for our present purposes the limit 

 appears to be a convenient one. 



Having thus glanced at the genus as a whole I propose to 

 confine my attention to the individual species, and here I am 

 met by a difficulty, which, in order to make myself more 

 clearly understood hereafter, I will deal with at once. I refer 

 to the nomenclature applied to two of the species. Unfor- 

 tunately the authors described these under one and the same 

 name, orbona. Now if we are to understand one another it 

 is necessary that we should decide to which of the two this 

 name should apply. Hufnagel, in 1767, described what we 

 know as the rarer of the two species under the name of 

 orbona, and Hubner, in 1776, figured it under the name of 

 S2ibsequa. In 1787, Fabricius described our commoner species 

 under the name of orbona, and subsequently (1793-1827), 

 Hubner applied the name of comes to it. From this we see 

 that Hufnagel being the first to use the name of orbona has 

 the prior claim to it, and he applied it to our rarer species. 

 The same name cannot be used for two species in one genus, 

 therefore Fabricius's orbona must sink, and Hubner's more 

 recent name of comes stand for our commoner species. I hope 

 I have made myself understood on this point, and, fortunately, 

 the names of the other species in the genus are too generally 

 accepted to need any remark. 



Of the six species inhabiting Britain five are of general 

 distribution, while of one the range appears to be somewhat 



