THE GENESIS OF SNAKES. 351 



In considering the relations which the snares of Orbweavers bear to 



those of other tribes, one cannot overlook the important characteristic 



which has been considered under the chapter relating to the 



isci viscid armature. That is to say, the characteristic snare of the 



Orbitelariffi consists of a series of straight lines covered with 



viscid beads, and disposed in the form of spiral concentrics, or spiral 



loops upon radiating lines lacking this viscid quality. 



Is there any trace of this remarkable characteristic in the spinningwork 

 of the other tribes? We have seen that the webs of Uloborus and Hypti- 

 otes are destitute of this peculiar armature, substituting therefor the floccu- 

 lent thread which has been heretofore described. We have also noted that 

 in this particular the spinningwork of the Orbweavers finds its homologue 

 in the snares of certain Tubeweavers, as, for example, Dictjma and Amau- 

 robius. Concerning Dictyna, it may be stated that so careful 

 and distinguished an observer as Bertkau, for example, offers the 

 opinion that this genus is provided with certain glands which secrete vis- 

 cid material that must be intermingled M'ith the flocculent spinningwork 

 which forms the cross lines of the typical snare. Undoubtedly the amount 

 of viscid material must be very small ; nevertheless, it is an interesting fact 

 that the organs for producing it should be found among the Tubeweaving 

 genera armed with the calamistrum. That the same organs exist in Ulo- 

 borus and Hyptiotes, the Orbweaving genera provided with calamistrum 

 and cribellum, I take for granted. 



As to the snare of Amaurobius, I think that no one who has ever ex- 

 amined it will hesitate to say that it is provided by the spider which spins 

 it with a considerable amount of viscid material. The way in 

 Sticky M-hich it sticks to one's fingers, and the entire characteristics of 

 Web ot ^-^^ thread when examined carefully, go to establish this point, 

 robius ^ liave not examined the genus by dissection, and cannot, there- 

 fore, speak from anatomical observation, but have no doubt at 

 all that Amaurobius will be found possessed, in a yet more decided degree 

 than the genera just noticed, with organs for the secretion of viscid ma- 

 terial. 



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. differens, I was 

 Are surprised to find it distinctly marked with viscid globules. (Fig. 



Therid- 345.) They were of an irregular character, but were manifestly 

 I,!;l°^^ , similar to those which form upon the snares of Orbweavers. 

 Viscid? Thinking that I might have been deceived by a little twist in 

 the line forming natural nodules, I examined carefully and often, 

 with the same conclusion, that the lines were beaded as with the webs of 

 Orbweavers. I have never met with a similar case, and scarcely know 

 what to think of this. Could it have been an abnormal act on the part 



