74 LEPIDOPTERA. 



arranged in a very irregular transverse row, beyond which is 

 a series of orange spots, black-edged, and lying in a white 

 marginal band. Hind wings with numerous black spots in 

 white rings ; a triangular white blotch beyond the middle, 

 followed by a row of orange spots, black-edged within, and a 

 marginal row of white-ringed black dots. 



Extremely variable in the size and number of the marginal 

 orange spots of the upper side, which in the male frequently 

 narrow off very small towards the apex of the fore wings, or 

 even become obsolete. This form of variation, which occurs 

 generally, becomes intensified in the North of England, par- 

 ticularly on the Durham coast, the orange spots of the upper 

 side being commonly absent in the male, and smaller in the 

 female, while a white edging has made its appearance round 

 the central black spot, and the black spots of the under side 

 are decidedly smaller. This is the variety named Salmacis 

 by Stephens. In Scotland a further divergence takes place, 

 the marginal row of orange spots is as in Salmacis. but the 

 black central spot has totally disappeared, its place being 

 taken by a bright white spot, and a similar alteration has 

 occurred in the under side, where the black spots have given 

 place to pure white. This form was long believed to be a 

 distinct species, under the name of Artaxerxes. The sequence 

 of variations from the type is, however, complete. In Scottish 

 specimens it is by no means rare to find the white spots of 

 the under side having a faint, dark, central dot ; and in the 

 South of England specimens are occasionally taken in which 

 the black spot of the upper side is more or less surrounded 

 with white. Mr. C. A. Briggs has one in which this spot is 

 pure white, though otherwise of the southern type. In 

 Durham all three varieties are foimd together. Mr. J. E. 

 Robson, of Hartlepool, says : " I believe that every form 

 occurs here, from those with a row of bright orange spots 

 round the upper side of the wings to specimens devoid of the 

 slightest trace of orange ; with black discal spot, and every 

 intermediate form, such as having a clear white ring round 



