184. AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
speaks of the four branches as radiating from the extremity of the sector.1 
Fig. 171, with the exception of the dotted line, is drawn from nature; so 
also are Figs. 172 and 173. These show, better than any worded descrip- 
tion, that the interradials are attached in the manner which I have repre- 
sented, and are not drawn out from a common apex or point. 
According to my view, the position of the first line spun is indicated 
by the dotted line (AA, Fig. 172). Afterward the first radius (1r) was 
formed by attaching that line to AA, thus drawing it up until it assumed 
the position of Aa, Aa. To this again were successively fastened the lines 
2r and 3r, which completed the radial framework, ready for inserting the 
spirals. So also, at Fig. 178, one sees the same order of progress as shown 
by the numbered lines, viz., the dotted original line drawn up to make the 
trapline and first radius (1st) by the attached thread, which constitutes the 
second radius (2d). The base line (8d) comes next in order, and there- 
after the two additional radii (4th, 5th) in their order. 
No doubt, the radial lines may be at times found meeting at or near the 
same point; I have certainly so found them, but I believe that this is not 
characteristic of the spinningwork, but is simply an accident thereof. In 
other words, the spider having made her first main line, attaches the three 
succeeding shorter ones to a convenient point thereon without much regard 
to whether they meet in a common angle or not, but in fact ordinarily 
places them at different points along the line. 
The framework being thus prepared, the spider proceeds to place in her 
spirals. For. the manner in which this is done we are indebted to Pro- 
fessor Wilder. His account is based upon two personal observa- 
tions of the mode of spinning. He says: “ Let us suppose that 
the framework of the net is completed, and that the first or 
longest interradial line (Fig. 174,11) has also been made. In- 
stead of beginning the second interradial at S* she begins at 4; and in- 
stead of climbing up the interradial or the strong and convenient base line 
(BB), she runs to a point (2) on the lowest radius near the apex, crosses 
the two intermediate radii from 2 to 3, and passes along the upper radius 
to the attachment of the first interradial (S1). On reaching this, she turns 
and moyes for about her own length toward the apex. Contrary to the 
usual habit of spiders, during this roundabout passage from 1 to 4 she 
spins no thread. She now spreads her spinnerets a little, and presses them 
upon the radius, keeping them so while she advances again about her own 
3 length. This forms the attachment of the second interradial 
ied (I?). The spider then lets her abdomen fall somewhat, support- 
pinning. | : E 
ing her body and advancing upon the line by means of her 
first, second, and third pairs of legs. The fourth pair are applied together 
to the spinnerets with great rapidity, at least five times in a second, or 
Mode of 
Spinning 
Spirals. 
1 Structure and Habits of Spiders, page 76. 
di hoot ati 5 2 al Sea 
