76 BRITISH BUTTERFLIES. 



equal breadth along the whole of the outer margin, and 

 at the lower corner is continued inwards for a short dis- 

 tance ; whilst in Hyale this border narrows rapidly, 

 and disappears before reaching the lower corner of the 

 wing. Also the dark border of the hind wings is much 

 broader in Edusa than in Hyale. Here we have dis- 

 tinctive marks, quite independent of the ground colour 

 of the wings. 



The sexes of this butterfly are nearly alike in their 

 markings, the chief difference being in the yellower 

 ground tint of the males. 



The same localities viz. the south and south-east 

 coast, and the adjacent district that are most prolific 

 in. its near relative, Edusa, likewise furnish this species 

 in the greatest plenty ; but this is by far the rarer 

 species of the two, and, either by coincidence, or in 

 obedience to some direct law, several successive periods 

 of its abundance have been septennial, or have occurred 

 once in seven years. Thus the years 1821, '28, '35, '42, 

 '49, and '56 are noted in entomological records as having 

 produced it in great numbers. 



On the coast of France, opposite to our own, it is 

 one of the common butterflies, and it is not improbable 

 that it frequently makes the passage of the Channel. 

 The maritime habits of both this and Edusa are well 

 known, and I have frequently seen the latter flying out 

 to seawards, and coquetting with the waves, till the eye 

 could follow the golden speck no longer. Taking ad- 

 vantage then of a favouring wind, its naturally strong 



