214 SPIDERS 



destruction of the entire migrating host, as there 

 is no return migration, and they are in most cases 

 blown out to sea and perish there. They concluded 

 that they were forced to migrate for this very reason 

 — to get rid of them on account of their excessive 

 numbers. And it was not an improbable notion for 

 the time they wrote in, during the early years of the 

 nineteenth century — quite half a century before the 

 doctrine of Evolution came into vogue, when the idea 

 of such interpositions or interferences with the order 

 of Nature began to fall into disregard. 



On the migrations of spiders I can throw no light. 

 The grass in any temperate region is alive with the 

 multitudes of these little aeronauts: on the pampas 

 they are so abundant that when the sun is low in 

 the west it casts a broad silver track over the grass 

 to the observer's feet, like moonlight on the water, 

 so covered is the surface of the grass with their 

 gossamer webs. And all the time, all the summer 

 long, one can see them perpetually drifting into the 

 air, to this side or that. Twice only have I witnessed 

 great migrations, when thousands of millions of the 

 minute creatures must have risen high into the air 

 at the same time, since for a whole day the sky was 

 full of the floating webs. This was in the late summer, 

 and a gentle wind was bearing them away in a north- 

 west direction. 



On the second occasion it was a local migration in 

 April — the very end of the migrating season — and the 

 direction was north, owing to a south wind at the 

 time. It really looked as if the little creatures had 



