396 CLASS ARACHNIDA. 



are always projecting, and often very simple ; the majority 

 have but four spinnerets, two of which, lateral or exterior, and 

 situated a little above the other two, are longer, with three 

 articulations, not reckoning the elevation formed by their 

 peduncle. They fabricate silken tubes, which serve them for 

 an habitation, and which they conceal, either in burrows that 

 they have excavated, or under stones, the bark of trees, or 

 between leaves. 



The theraphosae of M. Walckenaer will form a first 

 division, having for characters— four spinnerets, the two in- 

 termediate and inferior very short, and the two exterior 

 extremely projecting ; crooks of the forceps bent under- 

 neath along their keel or lower edge, and not within or on 

 their internal face ; eight eyes in all, most frequently grouped 

 on a small eminence, three on each side, forming, when 

 united, a reversed triangle, and the upper two approximate, 

 the other two disposed transversely, at the middle of the 

 preceding. 



The fourth pair of feet, and after them, the first, are the 

 longest ; the third is the shortest. 



In some the palpi are inserted at the upper extremity of 

 the jaws, so that they appear to be composed of six articula- 

 tions, of which the first, narrow and elongated, with the in- 

 ternal angle of the superior extremity projecting, performs the 

 office of jaw. The tongue is always small, and almost square ; 

 the last articulation of the palpi in the males is short, in the 

 form of a button, and bearing at its extremity the sexual 

 organs. The two anterior legs of the same individuals have 

 a strong spine, or spur, at their lower extremity. Such are 

 the characters of 



Mygale (proper), Walck. 



Some do not present at the upper extremity of their forceps 

 immediately above the insertion of the claw, or hook, which 



