S46 M. Hubert on an Emigration of Butterflies. 



is so active, as if I say that state of transition had made them 

 forget the memory of mutual relations. 



Concerning the butterflies, belles dames, isolated from their 

 birth, what singular cause could induce their uniting in such 

 numerous phalanxes, and determine them to quit their country 

 for a northern climate, mountainous and severe ? From what 

 region do they come, and in what place will they stop ? 



A fact so striking ought to have made some sensation in 

 other parts : These same butterflies, indeed, were seen in Pied- 

 mont by Professor Bonelli of the academy of Turin, before 

 they appeared in Switzerland. According to his account, giv- 

 en in a letter addressed to Mr Moricand, 13th January 1827, 

 the appearance of the thistle butterflies took place in the end 

 of March 1826, in the neighbourhood of Turin. These but- 

 terflies, though they stopped some time in places through which 

 they passed, went in a mass in a direction from south to north. 

 The air was filled with them, especially where there were 

 flowers, and at night all the plants were covered with them : 

 The 29th of May was the day in which they were most abun- 

 dant. A considerable number were seen during several days 

 following. Their numbers then sensibly diminished, but a 

 good many remained till the month of June. 



The fact was common in all the country, especially at Coni, 

 Racconni, Susa, &c. 



A passage similar to this had taken place at the end of the 

 last century. The Count of Locke has given a description 

 of it in the Memoirs of the Academy of Turin. There is lit- 

 tle doubt that a part of this column, a strong division, had 

 steered towards Switzerland, where it had most probably di- 

 vided itself in order to occupy our diff'erent valleys. 



I have reason to suspect that one of these parties had taken 

 the route along the valley of the Lake of Geneva, and had 

 reached that of the Rhone, having heard from the young en- 

 tomologists that the number of butterflies, belles dames, seen 

 this year in the environs of Lausanne as far as Bex, and even 

 to the mountains which end that valley, was infinitely greater 

 than usual. This beautiful butterfly without being rare, is 

 nevertheless not common in our country ; but this year, and 

 before I knew of their great emigratiou, I had myself observ- 



