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GEOGRAPHICAL DISTRIBUTION OF ORGANISMS 
359 
supplies the innumerable stragglers which every year reach 
Bermuda and the Azores. 
Insects. 
Winged insects have been mainly dispersed in the same 
way as birds, by their power of flight, aided by violent or long- 
continued winds. Being so small, and of such low specific 
gravity, they are occasionally carried to still greater distances ; 
and thus no islands, however remote, are altogether without 
them. The eggs of insects, being often deposited in borings 
or in crevices of timber, may have been conveyed long 
distances by floating trees, as may the larvae of those species 
which feed on wood. Several cases have been published of 
insects coming on board ships at great distances from land; 
and Darwin records having caught a large grasshopper when 
the ship was 370 miles from the coast of Africa, whence the 
insect had probably come. 
In the Entomologists Monthly Magazine for June 1885, Mr. 
MacLachlan has recorded the occurrence of a swarm of moths 
in the Atlantic ocean, from the log of the ship Pleione. 
The vessel was homeward bound from New Zealand, and in 
Lat. 6° 47' N., Long. 32° 50' W., hundreds of moths appeared 
about the ship, settling in numbers on the spars and rigging. 
The wind for four days previously had been very light from 
north, north-west, or north-east, and sometimes calm. The north¬ 
east trade wind occasionally extends to the ship’s position at 
that time of year. The captain adds that “frequently, in 
that part of the ocean, he has had moths and butterflies 
come on board.” The position is 960 miles south-west of 
the Cape Verde Islands, and about 440 north-east of the 
South American coast. The specimen preserved is Deiopeia 
pulchella, a very common species in dry localities in the 
Eastern tropics, and rarely found in Britain, but, Mr. Mac¬ 
Lachlan thinks, not found in South America. They must 
have come, therefore, from the Cape Verde Islands, or from 
some parts of the African coast, and must have traversed 
about a thousand miles of ocean with the assistance, no doubt, 
of a strong north-east trade wind for a great part of the distance. 
In the British Museum collection there is a specimen of the 
same moth caught at sea during the voyage of the Rattlesnake, 
