170 Mr. S. S. Saunders's Additional Observations, &)C. 



this notice is presented, it may be considered as the not unfre- 

 quent result of investigating the wonderful workings of instinct, 

 that the more we direct our attention to the subject, the more we 

 feel the want of more diligent research, and the insufficiency of 

 our attainable results. 



XXV. Observations on the Species of Spiders which in- 

 habit cylindrical Tubes covered by a moveable Trap- 

 door. By J. O. Westwood, F.L.S. kc. 



[ReadJanuary, 1840.] 



Of all the habitations constructed by annulose animals for their 

 own abodes, those cylindrical retreats lined with silk and fitted 

 to the size of the creature's body, are amongst the most inge- 

 nious. These are of two kinds: 1st, those which are moveable, 

 the creature generally weaving various extraneous materials into 

 the texture of the web, and often with the greatest regularity, 

 (amongst which I may particularly mention the nests made by 

 the caddice worms and the caterpillars of various Lepidoptera) ; 

 and 2ndly, those which are fixed, being formed either in vvood 

 or the earth. Instances of the latter are afforded by various 

 species of wild bees and wasps, but they are of a comparatively 

 rude construction compared with the cells of the trap-door spi- 

 ders. The interest excited by the accounts of these spiders has 

 been kept alive since the middle of the last century, when M. 

 Sauvages published his account of an " Araignee ma^onne," in the 

 Memoirs de I'Academie des Sciences, for 1758. This species 

 was the ^fygale ccementaria of Walckenaer, respecting which 

 M. Dorthes published some additional particulars in the second 

 volume of the Transactions of the Linnaean Society of London. 

 Another South European species, M. fodiens, Walck., A. Sauva- 

 gesii, Rossi, has afforded to M. V, Audouin materials for a very 

 interesting memoir, published in the " Annales de la Societe En- 

 tomologique de France," vol. ii. pi. 14. These species have been 

 separated from the genus I\Itjgale by Latreille, under the name 

 of Cteniza, but M. le Baron Walckenaer, in the first volume of 

 his " Histoire Naturelle des Insectes Apteres," has reduced them 

 again to a family of the genus Mygale. Our valued member, 

 S. S. Saunders, Esq., has laid before this Society the details of 

 the economy of another species, from Albania, which constitute one 



