TARSAL-COMB IX SPIDERS. 187 



entering upon other most interesting points, express a hope that we 

 have not exceeded the space which our kind editors have allotted us. 



Since the above was written, I have received the first volume 

 of an admirable work, on the spinning habits of American spiders, 

 by Dr. McCook, which has given me much pleasure in perusing, 

 in which he deals very fully, and in a charmingly analytical and 

 thoroughly scientific manner, with the various forms of webs and 

 silken products of spiders, chiefly of the group Orbitelarice, or 

 wheel- web spinners. Dr. McCook, in speaking on page 205 of 

 flocculent webbing, evidently also is under the impression, as I 

 have myself hitherto been, that spiders alone which possess the 

 calamistrum and cribellum, were capable of producing this peculiar 

 form of silk. 



Again, on page 351, he says, "One other fact remains to be 

 noted, and I confess that I speak of it with considerable hesitation. 

 On one occasion, while studying the snare of a species of 

 Theridium^ which I took to be T. diffe7'ens^ I was surprised to find 

 it distinctly marked with viscid globules." I am now in a position 

 to confirm this observation, and I surmise that it was probably not 

 an abnormal occurrence, as he suggests might have been the case, 

 because I have in many cases, I may say in all cases which have 

 come under my observation, noted rows of viscid globules, similar 

 to those on the webs of the Epiridce^ upon the crossing and per- 

 pendicular lines of the webs of Theridion tepidarioriim. 



I have, moreover, noticed during the process of enfolding 

 the victim, that the thread that is drawn out is often strung with 

 beads of viscid fluid, thus showing that probably the deposition of 

 these beads, and the spinning of the thread, are always done at 

 one and the same time. But the viscid globules do not appear upon 

 the flocculent wool hung around the web, so far as I have myself 

 observed. 



Again, there is another interesting point in connection with the 

 tarsal-comb. Dr. McCook has established the fact, that the 

 spiders of the group Theridiosoma Cambi-. spin snares of a deci- 

 dedly orbicular tendency : he has wondered if it were possible that, 

 what seemed to him to be spiral cross lines on the web, might be 

 a flocculent web of a spiral nature ; but he remarks that " this is 



