1832.] SPIDERS. 49 



returned ; and an hour afterwards I was much surprised 

 to find it with its jaws buried in the orifice, through which 

 the sting is protruded by the living wasp. I drove the 

 spider away two or three times, but for the next twenty- 

 four hours I always found it again sucking at the same 

 place. The spider became much distended by the juices 

 of its prey, which was many times larger than itself. 



I may here just mention, that I found, near St. F6 

 Bajada, many large black spiders, with ruby-coloured 

 marks on their backs, having gregarious habits. The 

 webs were placed vertically, as is invariably the case 

 with the genius Epeira : they were separated from each 

 other by a space of about two feet, but were all attached 

 to certain common lines, which were of great length, and 

 extended to all parts of the community. In this manner 

 the tops of some large bushes were encompassed by the 

 united nets. Azara* has described a gregarious spider in 

 Paraguay, which Walckenaer thinks must be a Theridion, 

 but probably it is an Epeira, and perhaps even the same 

 species with mine. I cannot, however, recollect seeing a 

 central nest as large as a hat, in which, during autumn, 

 when the spiders die, Azara says the eggs are deposited. 

 As all the spiders which I saw were of the same size, 

 they must have been nearly of the same age. This gre- 

 garious habit, in so typical a genus as Epeira, among 

 insects, which are so bloodthirsty and solitary that even 

 the two sexes attack each other, is a very singular fact. 



In a lofty valley of the Cordillera, near Mendoza, I 

 found another spider with a singularly-formed web. Strong 

 lines radiated in a vertical plane from a common centre, 

 where the insect had its station ; but only two of the rays 

 were connected by a symmetrical mesh-work ; so that 

 the net, instead of being, as is generally the case, circular, 

 consisted of a wedge-shaped segment. All the webs were 

 similarly constructed. 



* Azara's " Voyage," vol. i., p. ai> 



