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improbable that some considerable proportion would be found to 

 survive immersion in sea-water for several days. Many facts 

 have not been recorded as to the passage of beetles over wide 

 tracts of ocean, but some of them are sufficiently remarkable. 

 Darwin captured a Colymheies forty-five miles from land north of 

 the Eio de la Plata ; and at seventeen miles off Cape Corrientes 

 he caught in a net a number of live beetles of the genera Colym- 

 heies, Hydroporus, Hydrobius, Notaplms, Cynucus, Adimonia 

 and Scarahceus. A Calosoma also flew on board the Beagle when 

 ten miles from the shore of South America, and the Calosoma 

 sycophanta is believed occasionally to cross the English Channel. 

 Sir Charles Lyell also states, that exotic beetles are sometimes 

 thrown on our shores, which revive after being long drenched in 

 salt water. In the case of other insects, we have more positive 

 proof of their passage over wide spaces of ocean. A whole swarm 

 of locusts has been known to pass over Madeira from Africa, 

 a distance of more than 300 miles ; while Darwin himself cap- 

 tured a locust at sea 370 miles from land. Two individuals of 

 the Sphinx atropos flew on board the Hotspur East Indiaman in 

 1866, during an easterly gale, at a point 260 miles from the coast 

 of Portugal, and were exhibited at a meeting of the Zoological 

 Society. In his work on the ' Natural History of the Azores,' 

 just published, Mr. Godman relates that a white butterfly flew on 

 board a whaler coming from the south, at about 400 miles from 

 the Azores : it was caught by the captain and placed in a drawer, 

 where it laid several eggs. Such cases as these having been 

 already recorded, we may be sure that migrations to much greater 

 distances are constantly occurring, since we can hardly suppose 

 the extreme cases to be those which have first been observed. 

 We have therefore every reason to believe that, under favourable 

 conditions, almost any winged insect could traverse equal 

 distances. These considerations would lead us to the conclusion 

 that a partial identity of species may exist in the beetles of two 

 countries separated by some hundreds of miles of sea, without in 

 any way necessitating the former existence of a continuity of 

 land between them. In the case of the Atlantic islands, there- 

 fore, I see no reason to believe that they owe their Coleoptera to 

 a laud-connection with the continent, more especially when there 

 is such strong evidence against that view in the total absence of 

 all mammals and reptiles. Can we believe that the forests of 



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