248 JVotes on JVatural History. [May, 



leave a stream of splendor in their passage through the waves, 

 which alone prove sufficient to render their forms conspicuous to 

 the unaided eye. 



In approaching these shores, and long ere the land became vis- 

 ible, the ship was visited by an immense congregation of butter- 

 flies, of varied and interesting species, the greater proportion of 

 which were rather more than an inch in the expansion of their 

 wings. They fell upon the deck and rigging for a short time in 

 prodigious numbers and adhering to the various parts in such a 

 manner as to present the appearance of falling flakes of snow. 

 They were in all probability driven on their course by the pre- 

 vailing breezes from the land, and either became bewildered in 

 their flight, or were unable to make headway and regain the 

 shore in opposition to the continuous wind. 



The many instances of animals, and particularly insects, alight- 

 ing on vessels at great distances from the land, are facts exceed- 

 ingly interesting to the naturalist, inasmuch as they readily fur- 

 nish an explanation of one of the methods by which islands situ- 

 ated far remote from continents, have been visited, and finally 

 become populated by living forms, corresponding in every degree 

 with those peculiarly indigenous to these vast expansions of land. 



When we were in the parallel of the Canaries, about three 

 hundred miles to the westward of the nearest isle, two swallows 

 were observed flying about the ship, in an apparently much ex- 

 hausted state. In a short time one of them lit upon the ibre-yard 

 contiguous to the mast, and was without difficulty obtained. It 

 appeared extremely feeble and in a few moments it expired in my 

 hands. It proved to be the Hirundo rustica of authors. 



Charles Lucien Bonaparte, in a letter to the secretary of the 

 Linnean Society, dated from on board the United States ship Del- 

 aware, near Gibralter, states, " that being five hundred miles from 

 the coasts of Portugal, and four hundred from those of Africa, we 

 were agreeably surprised by the appearance of a few swallows, 

 (//. urbica and rustica) but what was my surprise in observing 

 several small warblers hopping about the deck and rigging. 

 These last were the Sylvia trochilus or hay bird." 



Soon after entering the trade-winds, in latitude 20 deg. 16 min. 

 north and longitude 23 deg. 2 min. west, we were greatly sur- 

 prised by the arrival on board of a large species of acrydium 

 (Grasshopper.) Our position was about one hundred and fifty- 

 one miles from, and nearly to windward of the Cape de Verd 

 islands, so that it is not altogether likely that this insect could have 

 worked its way for such a distance, almost directly in the wind's 

 teeth. The next nearest point of land, and from which the trade- 

 wind almost incessantly blows, is Cape Blanco on the African 

 coast, a distance of four hundred and twenty miles, a prodigious 



