SPIDERS AND MITES 235 



mon Spiders (Clubiona atrox), a long-legged and swift spe- 

 cies, that builds a compact cloth-like web in our outhouses, 

 with a gallery open at each end for retreat in danger. The 

 specimen is a part of the slough or cast skin, which you 

 may always find in the neighborhood of such a web; and 

 it is particularly suitable for examination, because it is 

 sloughed in the most perfect condition; every part, the 

 fangs, the palps, the legs with all their joints, the corneas 

 of the eyes, the entire skin with every hair all are here, 

 and all in situ, with a cleanness and translucency which it 

 would require much skill in dissection to obtain, if we 

 captured a living Spider for our purpose. 



There are in front of the head two stout brown organs, 

 which are the representatives of the antennae in insects; 

 though very much modified both in form and function. 

 They are here the effective weapons of attack. Each con- 

 sists of two joints: the basal one, which forms the most 

 conspicuous portion of the organ, and the terminal one, 

 which is the fang. The former is a thick hollow case, 

 somewhat cylindrical, but flattened sidewise, formed of 

 stiff chitine, covered with minute transverse ridges on its 

 whole surface, like the marks left on the sand by the rip- 

 pling wavelets, and studded with stout coarse black hair. 

 Its extremity is cut off obliquely, and forms a furrow, the 

 edges of which are beset with polished conical points re- 

 sembling teeth. 



To the upper end of this furrowed case is fixed by a 

 hinge-joint the fang, which is a curved claw-like organ, 

 formed of hard chitine, and consisting of two parts, a 

 swollen oval base, which is highly polished, and a more 

 slender tip, the surface of which has a silky lustre, from 

 being covered with very fine and close-set longitudinal 



