52 Lloyd's NAtURAL hiStorY. 



This Butterfly is widely distributed both in England, and on 

 the continents of Europe and Northern Asia, frequenting elm 

 trees and open bushy places. But it is local, and uncertain in 

 appearance, and is rarely common, though it occasionally 

 appears in amazing abundance, without any apparent reason. 

 Stephens' observations on this subject have often been quoted, 

 but are sufficiently interesting to be repeated here in full. 



"This species is usually esteemed a scarce insect in the 

 neighbourhood of London, and previously to the last season I 

 never saw it alive ; but the boundless profusion with which the 

 hedges, for miles, in the vicinity of Ripley, were enlivened by 

 the myriads that hovered over every flower and bramble- 

 blossom last July [1827], exceeded anything of the kind I have 

 ever witnessed ; some notion of their numbers may be formed 

 when I mention that I captured, without moving from the spot, 

 nearly 200 specimens in less than half-an-hour, as they suc- 

 cessively approached the bramble-bush where I had taken up 

 my position. How to account for their prodigious numbers I 

 am perfectly unable, as the same fields and hedges had been 

 carefully explored by me at the same, and different periods of 

 the year, for several preceding seasons, without the occurrence 

 of a single specimen in either of its stages ; and it is worthy of 

 remark, that the hedges to the north and north-east of the 

 village were perfectly free, although the brambles, c^x., were in 

 plenty. A few specimens were also taken near Windsor, and 

 in Cambridgeshire, and I believe near Ipswich, during the 

 past season. The entomologists of this last town, Mr. Kirby 

 informs me, do not esteem it a scarce insect ; its usual time of 

 appearance is the end of June, and sometimes till the middle of 



July." 



This species was mistaken by tlie older British ento- 

 mologists for the next, which had not then been taken in 

 Britain. 



