314 IXSECT ARCHITECTURE. 



which have been justly called mason-spiders by ]\I. La- 

 treille. One of these {Mygale nidulans, WALCK:^r.), found in 

 the West Indies, " digs a hole in the earth obliquely 

 downwards, about three inches in length, and one in 

 diameter. This ca\dty she lines with a tough thick web, 

 which, when taken out, resembles a leathern purse ; but 

 what is most curious, this house has a door with hinges, 

 like the operculum of some sea-shells, and herself and 

 family, who tenant this nest, open and shut the door when- 

 ever they pass and repass. This history was told me," 

 says Darwin, "and the nest, with its door, shown me by 

 the late Dr. Butt, of Bath, who was some joslts physician 

 in Jamaica."* 



The nest of a mason-spider, similar to this, has been 

 obligingly put into our hands by Mr. Eiddle, of Black- 

 heath. It came from the AVest Indies, and is probably 

 that of Latreille's clay-kneader (^Mygale cratiens), and one 

 of the smallest of the genus. AVe have since seen a pair 

 of these spiders in possession of Mr. William Mello, of 

 Blackheath. The nest is composed of very hard argilla- 

 ceous clay, deeply tinged with brown oxide of iron. It is 

 in form of a tube, about one inch in diameter, between six 

 and seven inches long, and slightly bent towards the lower 

 extremit}" — appearing to have been mined into the clay 

 rather than built. The interior of the tube is lined with a 

 uniform tapestry of silken web, of an orange-white colour, 

 with a texture intermediate between India paper and very 

 fine glove leather. But the most wonderful part of this 

 nest is its entrance, which we look upon as the perfection 

 of insect architecture. A circular door, about the size of a 

 cro^\ai piece, slightly concave on the outside and convex 

 within, is formed of more than a dozen layers of the same 

 web which lines the interior, closely laid upon one another, 

 and shaped so that the inner layers are the broadest, the 

 outer being gradually less in diameter, except towards the 

 hinge, which is about an inch long ; and in consequence of 

 al] the layers being united there, and prolonged into the 

 tube, it becomes the thickest and strongest part of the 

 * Darwin's Zoononiia, i. 253, 8vo. cd. 



