228 [October, 



opposed, so it seems to me, to the connection urged by Kirby, and 

 one seldom sees mixta in this country in June. Here, again, I think 

 the case is " not proven." 



While I am on the subject o£ the nomenclature of British species 

 of j3Sschna, I may as well allude to a third change in Kirby's Catalogue. 

 ^. rufescens,Y . d. L., becomes ^. isoceles (which should be corrected 

 to isosceles), Miiller (Nov. Act., iii, p. 125, 1767). The name occurs 

 amongst named varieties of ^^ g^iiadrifasciata" Miill. This particular 

 "variety" distinctly represents our rufescens, and indeed has long been 

 recognised as such ; the excuse for not giving the name precedence 

 being that it was originally applied to only a " variety." I do not 

 consider this objection a valid one, and am of opinion the species 

 should be termed JE. isosceles. 



I am painfully aware that great laxity existed, and still exists, in 

 connection with species of " Neuroptera " described by the " old 

 authors." Much as I dislike change, I accept it when a good case is 

 made out, but I object to change made without any given reasons, and 

 apparently often solely for the sake of the application of some old 

 name. 



Lewisham, London : 



September, 1898. 



WHAT IS LIBELLULA MNEA, Linne?: A STUDY IN NOMENCLATUEB. 



BY BOBBRT McLACHLAN, F.R.S., &c. 



Having occasion to consult the original descriptions in Linne's 

 works with regard to another species, I was struck with the discrepan- 

 cies that existed in connection with L. cenea, and though I found 

 afterwards that they had not escaped the notice of Charpentier and 

 Hagen (and perhaps others), the subject seemed sufficiently interesting 

 to allude to in detail, and more especially as it concerns the names 

 now in common use for two species, viz., ^^ Gordulia cenea, Linne," 

 and " Somatochlora Jlavomaculata, Yan der Linden." I propose to 

 deal with the works in chronological sequence. 



Fauna Suecica, ed. i (1746), p. 231. 



768. Lib. thorace viridi nitiao : lineis flavis alls pallidis abdomine nigro. 



Descript. : Caput et thorax viridia, nitida ; lineae duse flavse ad latera thoracis. 

 Abdomen cylindricum nigrum subtus flavum marginis colore dentato ; cauda di- 

 phylla angusta. 



