38 PJO DE JANEIRO. [chap ji. 



cally, as is invariably the case with the gemis Epcira : they were 

 separated from each other by a space of about two feet, but were 

 all attached to certain common lines, which were of g^reat leni^th, 

 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 gregarior.s spider in Paraguny, 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, wiien the spiders die, Azara says the eggs 

 are deposited. As all the spiders which I saw were of the ^ame 

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

 garious habit, in so tyjiical a genus as Epeira, among insects, 

 which are so bloodthirsty and solitary that even the two sexes at- 

 tack 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, aa 

 is generally the case, circular, consisted of a wedge-shaped seg- 

 ment. All the webs were similarly constructed. 



* Azara's Voyage, vol. i., p. 213. 



