THE VOYAGE OF THE BEAGLE 173 



cies), Notaphus, Cynucus, Adimonia, and Scavabaeus. At 

 first I thought that these insects had been blown from the 

 shore; but upon reflecting that out of the eight species four 

 were aquatic, and two others partly so in their habits, it 

 appeared to me most probable that they were floated into the 

 sea by a small stream which drains a lake near Cape Cor- 

 rientes. On any supposition it is an interesting circum- 

 stance to find live insects swimming in the open ocean seven- 

 teen miles from the nearest point of land. There are several 

 accounts of insects having been blown off the Patagonian 

 shore. Captain Cook observed it, as did more lately Captain 

 King of the Adventure. The cause probably is due to the 

 want of shelter, both of trees and hills, so that an insect on 

 the wing with an off-shore breeze, would be very apt to 

 be blown out to sea. The most remarkable instance I have 

 known of an insect being caught far from the land, was that 

 of a large grasshopper (Acrydium), which flew on board, 

 when the Beagle was to windward of the Cape de Verd 

 Islands, and when the nearest point of land, not directly 

 opposed to the trade-wind, was Cape Blanco on the coast of 

 Africa, 370 miles distant.* 



On several occasions, when the Beagle has been within 

 the mouth of the Plata, the rigging has been coated with 

 the web of the Gossamer Spider. One day (November ist, 

 1832) I paid particular attention to this subject. The weather 

 had been fine and clear, and in the morning the air was full 

 of patches of the flocculent web, as on an autumnal day in 

 England. The ship was sixty miles distant from the land, in 

 the direction of a steady though light breeze. Vast numbers 

 of a small spider, about one-tenth of an inch in length, and of 

 a dusky red colour, were attached to the webs. There must 

 have been, I should suppose, some thousands on the ship. The 

 little spider, when first coming in contact with the rigging, 

 was always seated on a single thread, and not on the floccu- 

 lent mass. This latter seems merely to be produced by the 

 entanglement of the single threads. The spiders were all of 

 one species, but of both sexes, together with young ones. 

 These latter were distinguished by their smaller size and 



The flies which frequently accompany a ship for some days on its 

 passage from harbour to harbour, wandering from the vessel, are soon lost, 

 and all disappear. 



