TRAP-DOOR SPIDERS. 87 



several parts and their functions might show us that 

 all spiders wliich 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.* 



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 re- 

 presented in the same way. 



* Tlie claws are probably of first-rate importance in tliis respect and should 

 be most carefully studied. M. Lucas has stated that the claws of Myijale 

 Blondii, and M. ni<jra from Algiers, and oi 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, s^r. 2, torn. ix. 1857, p. 587, and Ann. de la Soc. Entom. de France, 

 ser. 3, torn. 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 

 TerritdaricB, or Mygalidce as he terms them, " have the inferior surface 

 of their biuugrdate tarsi, and of the digital joint of their pediform 

 palpi, in the females, densely clothed with compound, hair-like papillae, 

 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 aud are destitute of hair-like 

 pajiillse on the legs aud palpi." 



The four species of trap-door spider on the Riviera, here described, ap- 

 pear to form exceptions to this rule, however, for they all remained heljdess 

 prisoners when placed in a glass tumbler, though struggling vigorously for 

 free<lom. 



When, however relying on th's experience, I placed a number of smaller 

 spiders of different kinds in glasses for examination some walkeil stiaight 

 out without any difficulty, while others wei'e unable to climb uj) the sides. 



