THE ARMATURE OF ORBWEBS: VISCID SPIRALS. 81 
which the spider all the while has been rapidly approaching, and grasps 
it with the claws just beneath the point where the new string will cross. 
This then is the attitude of the spider at this point of her operations. 
Fig. 79. One hind foot (4.0) grasps the radius near and below the point 
(xx) just opposite the last point of 
attachment. The other 
Paying hind leg (4.i) is reached 
ee Be ott beyond and above the 
read. F 
spider’s abdomen, hold- 
ing the new string (ns) so that the 
two parts form an angle. Now the 
abdomen drops towards the radius. 
The raised foot lets go the stretched 
string at the very moment that the 
spinning fingers grasp the radius 
(at xx) and clamp the string there- 
to. The string being released at 
the same moment, contracts with 
a sudden snap, and thus forms the 
little interradial or portion of the 
spiral line between the two radii. Fig. 80 shows the first action in this 
process. The strings I I, II I, are sections of a finished spiral line, and 
III x III is a string in the act of being spun. The line x is caught up 
by the claw, cl, upon a tarsal spine, ts, (apparently) or a metatarsal spine, 
ms, and pulled out from the abdomen to which it is attached by ab. The 
foot (here greatly exaggerated) moves rap- 
idly towards ab, and the line is fastened at 
the point III, indicated on the right hand 
radius, r. The large tarsal spines which arm 
the terminus of the tarsus of Argiope coph- 
inaria are continually used by that species 
to hold the beaded string as it is thus 
drawn out. In the meantime, of course, 
the remaining limbs of the spider have 
been carrying her forward. The 
legs on the side towards the cen- 
tre of the hub reach upward and 
grasp the spiral scaffold (ss) if 
the scaffold happens to be within reach. 
This is frequently the case during the 
whole process of spinning; but frequently also during the placing in of 
the first spiral strings included between two scaffold lines the spider is 
unable to reach so far, and therefore must go around the radius, as will 
be described presently. The legs on the side of the body towards the 
Fic. 79. Clamping a spiral string. 
The 
Forward 
Progress. 
Fic. 80. Drawing out a beaded spiral. The 
leg much exaggerated. 
