TRIFID^. 71 



obliterated, and the stripes distinct ; or the ground colour is 

 wholly fulvous, or red-brown, or purple-brown, with the same 

 range of markings ; or the two large angulated spots in the 

 discal cell are black, and the costa spotted with black ; or the 

 dark spots are obliterated, and the whole surface is unicolorous 

 or nearly so. Rarely the entire surface is yellowish-drab, 

 except the two chocolate-coloured angulated spots ; occasion- 

 ally the basal half of the wings being normal, the outer half 

 is abruptly and intensely purple-red ; or is so from the 

 middle to the subterminal line. Every possible intermediate 

 variation occurs, and to enumerate all the phases of colour and 

 markings in these Southern forms is practically hopeless. In 

 the hind wings the colour varies from white to dark grey-brown. 

 The thorax usually follows the colour of the fore wings. 



In the hill districts of the north of England and in most 

 parts of Scotland is a local or climatal range of forms, de- 

 cidedly smaller in size, with the fore wings a little narrower 

 and more blunt at the apes ; usually also of more uniform 

 colouring, the tendency of the ground colour being to reddish- 

 brown or fulvous ; the markings identical, though rarely 

 distinct, and having a range of variation in colour and in 

 markings, which, though usually less pronounced, is practi- 

 cally the same as that already detailed, but a shading of 

 purple-grey is much more general, while the angulated spots 

 in the discal cell are almost always purple-brown, very rarely 

 black. In these forms the hind wings have, in some instances, 

 a pale shade across the middle, or a dark cloud along the hind 

 margin, but usually are as in the larger forms. Both occur 

 mixed together where the bases of the hills are wooded, and 

 with them all possible intermediates. This smaller hill- 

 frequenting form is known on the Continent under the name 

 of N. conjiua, and has been considered a distinct species. 



Another, and very different form, has been discovered 

 within the last few years, accompanying those already de- 

 scribed, in the Shetland Isles, having decidedly more pointed 

 and narrower fore wings, their costal and dorsal margins 



