( i ) 



form. So far from following the broadened contour of the 

 specimens from Algeria and Cannes, those from Belgium, 

 Switzerland, Spain and Greece might have been captured 

 in our southern counties for anything that their scent-scales 

 show to the contrary. The same may even be said of a speci- 

 men from the Tian Shan, though here, perhaps, there is a slight 

 broadening of the distal portion as in some of the bryoniae. 

 Altogether it does not seem possible to attach any geographical 

 significance to these variations of outline. 



" My friend Dr. Bltringham has been so good as to make 

 preparations of the genitalia of all the forms that I have 

 mentioned, and also to prepare outline drawings of them. 

 These I will show upon the screen in the same order as the 

 corresponding scent-scales; and I think it Mall be seen that 

 they are even more uniform in type than the scales, and that 

 it is difficult, or perhaps impossible, to detect any correlation 

 between such variations as do exist in the two structures. 



" There are certain forms which are acknowledged to be 

 closely related to P. napi, and which indeed might without 

 much violence be regarded as conspecific with it. I refer to such 

 forms as P. oleracea, Harris, of North America, and P. melete, 

 Menetr.j from Central and Eastern Asia. All these have 

 scent-scales of the napi form, though in some, as in two speci- 

 mens which I think must rank as melete, from Thundiani on 

 the borders of Kashmir, and the Island of Tsu-Shima respec- 

 tively, the accessory disc is enormously large in comparison 

 with that of other allied forms. A specimen from Japan, 

 which corresponds perhaps with ajaka of Moore, has a scale 

 like that of a napi from Spain ; while oleracea from Vancouver 

 has a rather narrow but quite napi-hke scale with a strong 

 tendency to the formation of spiny prolongations to the 

 cornua. I am again indebted to Dr. Eltringham for prepara- 

 tions and drawings of the genitalia of these forms. There is, 

 I think, nothing to distinguish them from those of P. napi. 



" I have found in many cases that there are constant differ- 

 ences between the shape of scent-scales according to their 

 position on fore- or hind-wing. In order to avoid errors 

 arising from this source I have in all instances except the first 

 P. napi (Oxford), taken the scales from the same situation, 



