APATURA IRIS. 125 



margin of the hind-wings are whitish-blue. The knobs 

 of the antennae are tipped with brown, and but slightly 

 thickened. The sexes are similar. 



A variety sometimes occurs in which the arrangement 

 of the under-surface is very much altered, and in which 

 the upper surface is without the white spots. 



Apatura, Fabr. 



In the genus Apatura the larva seems to be inter- 

 mediate between the genus Limenitis and the Ringlet 

 group. It resembles the latter in having no spines, and 

 in tapering towards both extremities, especially towards 

 the anal one, which is slightly bifid. In shape it is 

 limaciform, or slug-like. It differs from the Ringlets, and 

 resembles the last genus, Limenitis^ in having on the head 

 two processes somewhat resembling ears. The pupa is 

 neither angled nor spine-bearing ; it is very much flattened 

 laterally, and is suspended by the tail. The imago some- 

 what resembles that of the last butterfly (Limenitis sibylla\ 

 but it has one or two eye-spots, which remind us of the 

 Ringlet group. The wings are large and powerful, and 

 the flight is strong. There are but four legs adapted for 

 walking, the anterior pair being only slightly developed. 

 The genus is represented in Britain by one species only. 



A. iris, Linn. (Purple Emperor) (Figs. 130 to 133), no 

 doubt derives his English name from the purple robe with 

 which he is adorned, but the " Empress," though similarly 

 marked, is without the purple sheen which gives the glory 

 to her mate. This monarch of the butterfly tribe adopts as 

 his throne the topmost branch of an oak, where he sits 

 aloft in the sunshine, occasionally sailing away almost out 

 of sight, doing battle with his peers, the monarchs of the 

 neighbouring oaks, and returning as a rule to the identical 

 spray from which he started. While the Emperor is there 



