I&33-] AERONAUT SPIDERS. ttzj 



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 specimens, but those which I preserved belonged 

 to the genera Colymbetes, Hydroporus, Hydrobius (two species), 

 Notaphus, Cynucus, Adimonia, and Scarabaeus. 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 

 Corrientes. On any supposition it is an interesting circumstance to 

 find live insects swimming in the open ocean seventeen miles from the 

 nearest point of land. There are several accounts of insects having 

 t<;en blown off the Patagonian shore. Captain Cook observed it, as 

 did more lately Captain King in 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, three hundred and seventy 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 1st, 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 flocculent 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 more dusky colour. I 

 will not give the description of this spider, but merely state that it does 

 not appear to me to be included in any of Latreille's genera. The 

 little aeronaut as soon as it arrived on board was very active, running 

 about, sometimes letting itself fall, and then reascending the same 

 thread ; sometimes employing itself in making a small and very 

 irregular mesh in the corners between the ropes. It could run with 

 facility on the surface of water. When disturbed it lifted up its front 

 legs in the attitude of attention. On its first arrival it appeared very 

 thirsty, and with exserted maxillae drank eagerly of drops of water ; 



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

 passage from harbour to harbour, wandering from the ves?ti, Are oon lostj 

 nd all disappear. 



