230 



which they are armed, varies not inconsiderably within the same 

 species. The number of spines on the legs sometimes offers good 

 distinguishing marks; but the most important and certain are, as 

 has been said, those that are drawn from the form and armature of 

 the organs of copulation. 



In the cf of the species in question the pars tibialis of the 

 palpus has, on the underside, a very short, compressed or longitu- 

 dinally grooved process, usually truncated at its termination; the 

 outer side of the joint is drawn out into a longer or shorter, more 

 or less pointed, coarse spine, lying close to the external edge of the 

 lamina bulbi or pars tarsalis. This lamina has usually, on its outer 

 border, a blunt, more or less soft or transparent process. The bul- 

 bus itself in general exhibits a very long, fine spine or coarse bristle, 

 curved round the bulbus on the sides and in front, and closely 

 adjoining the margin of the cavity, in which the bulbus is included; 

 the point of this long spine is sometimes curved upward and either 

 enclosed in or lying along the transparent process on the outer bor- 

 der of the lamina (particularly clearly in X. eristatus). On the under 

 side of the bulbus may generally be found one or two spines or 

 processes, the different position, form, and number of which offer 

 particularly good marks of distinction. — The female's vulva usually 

 consists of one or two fovese, and also exhibits constant but less easily 

 observable differences in the various species. 



The species of the genus Xysticus described by Westring, and 

 to which we here chiefly refer, are his Thomisus lanio, bifasciatus, 

 eristatus, calcaratus , audax, cinereus, ulmi and sabulosus. The other 

 are comparatively easy to distinguish; and for them also the organs 

 of copulation present excellent characteristics. 



(Pag. 412). 1. Th. lanio [= Xysticus impavidus sr. ')J« 



Syn.: ?1845. Xysticus lanio C. Koch, Die Arachn., XII, p. 77 (ad part.:) Tab. 



CCCCXIV, fig. 1010. 

 1851. Thomisus ,, Westr., Ported™, etc., p. 50. 

 1865. Xysticus ,, Ohl., Arachnol. Studien, p. 7 (ad part.). 



l ) Xysticus impavidus N. — Mas. Cephalothorax c:a 3 y 4 millim. longus , dorso 

 leviter arcuato, fronte paullo rotundata, non exacte truncata; ferrugineo-fuscus, 

 vitta media lata fusco-testacea , macula ordinaria fusciori partis cephalicae in late- 

 ritras rotundata, postice breviter acuminata; postice utrinque macula nigra nota- 

 tus. Palpi testaceo-fusci, lamina obscuriore , bulbo nigro ; pars tibialis parte patel- 

 lari dimidio brevior, procursu laterali longitudinem ipsius partis jequanti, recto, 



