VAEIATION OF CERTAIN AGROTID^J. 201 



mind. Some specimens of this variety, which came through a 

 well-known lepidopterist into my hands, from Dr. Staudinger, are 

 altogether unlike all my previous tliought of what ohelisca ought 

 to be, and altogether unlike the type ofruris, Hb., fig. 4 16, which is a 

 streaked form. They are like some of my specimens of tritici which 

 1 called cursoria-like, i.e., they are without the pale costa, without 

 the pale longitudinal markings ; in fact, they bring us back to 

 the root of the matter again, viz., that tritici and ohelisca have 

 cursoria-\\\se forms, whilst cursoria has the streaked tritici-Wka 

 forms, and that these varieties run in their extreme forms into 

 each other so much, that it is onl}^ by training the eye specially 

 that there is any real difierence to be detected between any one 

 of tlie species and the allied ones (if they can be considered as 

 species) ; for the members of the whole group are so closely 

 interwoven one with the other, that it is most difficult to tell 

 where one ends and the other begins. However, I have tried 

 to explain some of the difficulties of this difficult group 

 without giving, except in the case of aquilina, and this, I 

 think, is almost generally admitted now, any undue prominence 

 to my own opinions. 



Before concluding I may state what my opinions are : — 



1. I firmly believe, and consider it impossible of contradiction 

 which can be proved, that aquilina is a pretty generally dis- 

 tributed variety of tritici which has never become localised, and 

 wljich freely interbreeds with typical tritici, and is therefore 

 altogether, on any ground whatever, unentitled to rank as a 

 species. 



2. That cursoria is also an extreme development of a par- 

 ticular form of tritici, which has become specially modified and 

 constant within certain limits, that the specimens breed inte7' se, 

 although it is not known whether cursoria cojjulates with tritici 

 when occupying the same ground. I am inclined to believe that 

 it does not, and that it is what Dr. Staudinger would call a 

 Darwinian species. 



3. That ohelisca is a still more highly specialised form, and 

 that its constancy in Britain may be either a proof of its more 

 complete development, or owing to its greater rarity, a proof of 

 our ignorance in not knowing the different forms of variation 

 through which it may extend. 



I have had even good lepidopterists ask me how it is that 



