CLOUDED SULPHUR. 57 



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 

 and rapid flight would quickly take it across the few 

 miles of sea that separate us from the Gallic shore. 



Hyale, whose flight is at least as strong as Edusa's, 

 and whose salt-water tastes are similar, doubtless acts 

 in the same manner. 



The northward range of this species is more limited 

 than that of Edusa, but it has been taken singly near 

 York, Manchester, and a few other northern localities. 

 In the lucerne fields near Brighton, a dozen or more 

 have been sometimes captured in one day. 



The caterpillar is of a sea-green colour, with four 

 yellow lines, two along the back and one on each side ; 

 and is to be found, in June and July, feeding on lucerne 

 and other plants of the same natural order. 



The chrysalis is very similar to that of Edusa, green, 

 with a yellow stripe. 



In this country, the butterfly first appears in August ; 

 but on the Continent it seems to be double-brooded, 

 being found in May as well as in August. 



