SB RIO DE JANEIRO. [chap lu 



cally, as is invariably the case with the genus 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 gregarioi;s 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 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, as 

 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. 



