APPENDIX. 139 



such a manner that even when the outer earthy part has 

 become cracked, or been torn away by the action of the rain, 

 they remain firm and fit to conceal their inhabitant. I have 

 often found the tubes of web thus left exposed, as they are 

 represented in Plate L, Fig. 4, situated in the cement of a 

 wall, and among Lyeopodium dentlcidatum, Adiantuni 

 Capillus- Veneris, Marcha7itia polymorpha, and other small 

 plants. And it seems that the animal, perceiving the nature 

 of the soil, takes care to reinforce the silken case, so much 

 the more as she finds the earth less firm, and rice versa. So 

 that in burrows excavated in solid ground, with the exception 

 of a little space close to the aperture, the nest is merely 

 smoothed and daubed ; while sometimes the spider constructs 

 a tube so strong that it supports itself even when deprived of 

 all the earth, the animal having had the foresight to attach 

 it along the course of the clefts of the rock, or to the cement 

 of the pieces of tufa in the wall, as represented in Plate I. 

 They have often also a double aperture, and the upper por- 

 tions of the burrows converging, meet and anastomose at about 

 two inches distance. The aperture is closed by a little door or 

 valve (a), which, having its hinge in the upper part and a little 

 on one side, falls by its own weight, and fits itself exactly to the 

 opening. The outer surface of the wicket is covered with 

 earth, cemented by the glue of the spider, so that it is ren- 

 dered imperceptible to common eyes, and the industrious 

 little creature takes care to leave around the aperture a Kind 

 of rim, to which the door fitting closely, leaves no passage for 

 any animal, nor does it show its edges. At the bottom of its 

 tube the creature keeps her numerous offspring, and always 

 stands herself as sentinel at the door, holding the wicket 

 raised by means of the four anterior feet, and the palpi, curved 

 extremities of which she inserts between the rim of the tube 

 and of the door, as represented in a' f. Sometimes, however, 

 they do not appear, but she leaves only the chink for observa- 

 tion, as one sees in a of the same figure. Fig. 2, at c, repre- 

 sents the aperture of an abandoned burrow, and at d the 

 raised door of another burrow, with its almost funnel-shaped 

 aperture. That which Sauvage, Olivier, and Latreille relate 

 of her is not true — namely, that she remains at the bottom of 



