SPIDERS AXD MITES. 213 



microscope, so as to make out their structure. If we 

 confine the Spider in a glass cell, it is so restless that the 

 least shock or change of position will cause it to move to 

 and fro ; and, besides, when it does become quiescent, 

 the spinnerets are closed in towards each other, so that 

 we cannot see their extremities. By selecting a speci- 

 men, however, recently killed, such as this Clubiona, we 

 may discern sufficient to enable us to comprehend their 

 construction. 



Looking, then, at the abdomen from beneath, we see 

 the three pairs of spinnerets clustered together close to 

 the extremity. The pair most forward are shaped some- 

 what like barrels, whose free ends bend over toward each 

 other. They are covered with stiff black hairs, and just 

 within the margin of what may be called the head of the 

 barrel (for it is cut off horizontally, with a sharp rioi), 

 there is a circle of very close-set, stiff, whitish bristles, 

 which arch inwards. The whole flat surface of the 

 " head," within this circle of bristles, is beset with very 

 minute horny tubes, standing erect, which are the 

 outlets of the silk-ducts that belong to this pair. 



Behind this first pair are seen the middle pair, almost 

 concealed, however, from their shortness and smallness, 

 and from the approximation of the first and third pairs. 

 We can discern that thev are more teat-like than the 

 preceding, terminating in a minute wart, which is pro- 

 longed into a horny tube. The whole teat is set with 

 similar tubes, which are larger and longer than those of 

 the first pair. Finally, the third pair resemble palpi, for 

 each consists of two lengthened joints, and are bluntly 

 pointed. The spinning tubes in these are limited, as it 

 appears to me, to one or two at the extreme end of each 

 spinneret, the whole surface besides being covered with 

 the ordinary long bristles. Strictly speaking, however,, 

 they are three-jointed, for all the spinnerets spring from 

 wart-like sockets, which may be considered as basal 



