THE GENESIS OF SNARES. 349 
rinthea, and Thaddeus (Fig. 341), and, indeed, by all the nest making 
species, such as the Furrow, Insular, and Shamrock spiders. This feature 
of their spinningwork is readily ac- 
counted for, and appears most closely 
to connect that tribe with the other 
tribes of the spinning fauna. It is, 
however, far more difficult 
to explain the origin of 
such a remarkable habit as 
the construction of an orbicular snare 
of that geometric character with which 
the reader is now familiar. We ap- 
proach it, however, from the direction 
of the Tubeweaving genera, as Dic- 
tyna and Clubiona. The fact has 
heretofore been -alluded to, that they 
are provided with special organs, the 
eribellum and calamistrum, for the 
exudation and preparation of a floc- 
culent thread out of which their trap- 
ping lines are spun. These threads 
are placed upon lines composed of or- 19-548. The snare os ane via city a 
dinary spinningwork, which usually 
diverge with more or less regularity from some common point. The manner 
of placing them is well illus- 
trated by Fig. 342, where the 
curled thread is seen spread 
along its supporting lines, and 
passed from one line to anoth- 
er, and so back and _ forth 
throughout the snare. 
This would seem to be a 
most natural movement. It is 
precisely the one which, as we 
have explained (see Fig. 95, 
: Chapter VI.), is re- 
Dictyna’s sorted to by Argiope 
ee cophinaria and Argi- 
— Thread. Ope argyraspis when 
: Fae they form the zigzag 
Fig. 844. Orb like snare of Dictyna philoteichus, woven band which adorns and charac- 
2 ail terizes their round web. It is 
naturally produced by the striding movement of a spider between two 
lines, swinging her abdomen backward and forward as she moves. In 
Origin of 
Orbwebs. 
