258 LEPIDOPTERA. 



upper side repeated and equally distinct, though not of so 

 glossy a black ; but the orange stripes very faint ; a broad 

 stripe of very pale yellow lies along the costal margin. Body 

 orange-yellow ; legs purplish-brown. 



Excessively variable, in the number of black spots, in their 

 size, and in the degree to which they are separated or massed 

 together — but the inner row of the series occupying the 

 position of a second line is usually united in some degree, 

 and often becomes a stripe, or broken stripe, with hardly a 

 semblance of the round spots. Beyond this, variation seems 

 to be rather local in its distribution. In South Wales I have 

 found the ground colour rendered dusky by a thick, or thin, 

 sprinkling of minute black dusting over the white surface ; 

 in the fens of Norfolk a tendency to blackening of the fore 

 wings by the running of the black spots into elongated stripes 

 along the nervures ; and in many southern districts to dimi- 

 nution of the black spotting so that the white surface is 

 greatly increased, and consequently the general brightness of 

 the insect is enhanced. But it is to Lancashire and other 

 North-western districts and South Yorkshire that we are 

 mainly indebted for a knowledge of the capabilities of this 

 species for extreme variation ; and to describe all the results 

 of the constant rearing of specimens for many years would 

 tax the energies of the most laborious and diffuse writer. In 

 the majority the markings of the fore wings are altered by 

 the extension and massing together in every possible degree 

 •of the black markings, sometimes in very broad, or doubled 

 black bands, sometimes in a latticing of such bands and 

 longitudinal stripes, occasionally in the extinguishment of 

 the yellow or orange stripes, and in one most striking, and 

 indeed famous, form, by the amalgamation of black markings 

 so as to form a complete uniform sufiusion of the fore and 

 hind wings with black, except a pure white band across 

 them all at some little distance from their base. Of this 

 unusually definite and well-marked variety a considerable 

 number are said to have been reared by one collector near 



