several parts and their functions might show us that all spiders which spin similar webs are furnished with equivalent instruments, so that what one leg lacks another may possess in some shape or another; brushes of stiff hairs in one place, compensating for a toothed claw, or for a row of moveable spines in another.[1]
It would be interesting, from this point of view, to draw all the parts which may be supposed to aid in the act of weaving, and so to contrast the corresponding limbs of different spiders, the nests of which are known, that one might see at a glance in what they differed and agreed. I have done this for the falces and the last joint of the foremost right foot of the four spiders figured in Plates VII., VIII., IX., and XII., but to make the case complete all the limbs should be represented in the same way.
- ↑ The claws are probably of first-rate importance in this respect and should be most carefully studied. M. Lucas has stated that the claws of Mygale Blondii, and M. nigra from Algiers, and of M. nigra and M. avicularia from Brazil, are retractile like those of a cat! Unfortunately the dwellings of these spiders have not been described. See Lucas (H.) in Rev. et Mag. de Zoologie, sér. 2, tom. ix. 1857, p. 587, and Ann. de la Soc. Entom. de France, ser. 3, tom. v. p. cxx., and vi. p. clxxi. Another curious point in which spiders differ is the presence or absence of viscidity in the hairs which clothe their feet and palpi. Mr. Blackwall states (Spiders of Great Britain and Ireland, vol. i. p. 13), that by far the greater number of the suborder Territelariœ, or Mygaliœ as he terms them, "have the inferior surface of their biungulate tarsi, and of the digital joint of their pediform palpi, in the females, densely clothed with compound, hair-like papillæ, constituting an apparatus which, by the emission of a viscous secretion, enables them to traverse the perpendicular surfaces of dry, highly polished bodies; others have three pairs of spinners and are destitute of hair-like papillæ on the legs and palpi." The four species of trap-door spider on the Riviera, here described, appear to form exceptions to this rule, however, for they all remained helpless prisoners when placed in a glass tumbler, though struggling vigorously for freedom. When, however relying on this experience, I placed a number of smaller spiders of different kinds in glasses for examination some walked straight out without any difficulty, while others were unable to climb up the sides.
