FLOCKS UF BUTTKKFLIKS. 203 



flocks of countless myriads, extended as far as the 

 eye could range. Even by the aid of a telescope 

 it was not possible to see a space free from butter- 

 flies. The seamen cried out " it was snowing but- 

 tei-flies," and such, in fact, was the appearance. 

 More species than one were present, but the main 

 part belonged to a kind very similar to, but not 

 identical with, the common English Colias edusa. 

 Some moths and hymenoptera accompanied the 

 butterflies ; and a fine beetle (Calosoma) flew on 

 board. Other instances are known of this beetle 

 having been caught far out at sea ; and this is the 

 more remarkable, as the greater number of the 

 Carabida3 seldom or never take wing. The day 

 had been fine and calm, and the one previous to it 

 equally so, with light and variable airs. Hence 

 we cannot suppose that the insects were blown off" 

 the land, but we must conclude that they volunta- 

 rily took flight. The great bands of the Colias 

 seem at first to afford an instance like those on 

 record of the migrations of another butterfly, Va- 

 nessa cardui ;* but the presence of other insects 

 makes the case distinct, and even less intelligible. 

 Before sunset a strong breeze sprung up from the 

 north, and this must have caused tens of thousands 

 of the butterflies and other insects to have perished. 

 On another occasion, when seventeen miles off" 

 Cape Corrientes, I had a net overboard to catch pe- 

 lagic animals. Upon drawing it up, to my surprise 

 I found a considerable number of beetles in it, and 

 although in the open sea, they did not appear much 

 injured by the salt water. I lost some of the spe- 

 cimens, but those which I preserved belonged to 

 the genera Colymbetes, Hydroporus, Hydrobius 

 (two species), Notaphus, Cynucus, Adimonia, and 

 Scarabceus. At first I thought that these insects 

 * Lyeli's Principles of Geology, vol. iii., p. 63. 



