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THE ARMATURE OF ORBWEBS: VISCID SPIRALS. 83 
which she has carried around with her. This makes one section or string 
of her beaded spiral. The next string, C-D-E, is completed in the same 
way, the general course being in the direction of the arrows. 
course of 4s the space between the newly made viscid spirals (as A 
Spider: 8 the space between the newly made viscid spirals (as ) 
and the next occurring foundation spiral (SFx) is diminished, 
the spider does not need to walk along the intervening radii, 1R, 2R, ete. 
The distance between the spiral foundation and the new points of opera- 
tion is then short enough to allow her to grasp the former with her fore 
feet; and thus she strides along, oscillating between the viscid spirals and 
the foundation spiral, and between the two radii separating the beaded 
string which she is weaving in. Very often, indeed, there is no need to 
walk along the radius at all, but from the beginning to the end the 
spider is able to accomplish her work by the simple process of reaching 
to the spiral scaffold. In that case, of course, the dotted line and arrows 
of Fig. 81 only represent in a general way the course of the body. 
In ascending the orb, as well as in crossing from one side to. another, 
the aranead must plod through all the course which has thus been imper- 
fectly indicated; but when she is on the downward course she 
is not compelled to stride along the radii and spiral scaffolding, 
and therefore simply drops from the point of attachment last made to the 
next radius. (Fig. 82.) This sheer descent of her web is made when those 
radii are reached which cross from the centre laterally to the circumfer- 
ence, when it is manifest (see R1, R2) that all required is that she should 
drop from the radius last intersected (R2) to the one next in order (R38). 
This is the usual course of the spider, and not until she makes the turn 
and again proceeds laterally across her orb is she required to renew the 
more tedious process described. 
It is obvious that those Orbweayers which make vertical webs must, 
from necessity of the case, vary their mode of proceeding while spinning 
the spiral lines, according to the position which they may chance 
at the time to have upon their orbs. This fact may be illus- 
trated at Fig. 83, which represents diagramatically the progress 
of the spider around an entire concentric. The web is represented with the 
radii, R, R, in place, and the spiral scaffold, S, located. The spider had 
already begun upon the viscid spirals, and had laid in one circular course 
of the series. Let us suppose that she starts at the point x on radius marked 
R1, to lay in her second spiral concentric. The ordinary course would be 
to stride along the radius to the spiral scaffolding (S) and so to the point 
x2, where she would fasten her new string. But it is obvious that such a 
course would be wasted time and energy, and that her purpose would be 
accomplished more readily by dropping directly from x on R1 to R2, and 
carrying her line to the point of junction x onthe last named radius. This 
is precisely what the spider does, and this is her habitual method on all 
parts of her orb where such a direct drop is practicable. 
Dropping. 
Swinging 
the Circle. 
