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 r^om 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 (Ir) 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. 173, 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 (3d) 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 

 Spirals ' ^ e framework of the net is completed, and that the first or 

 longest interradial line (Fig. 174, I 1 ) has also been made. In- 

 stead of beginning the second interradial at S 4 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 (S 1 ). On reaching this, she turns 

 and moves 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 

 length. This forms the attachment of the second interradial 



(I 2 ). The spider then lets her abdomen fall somewhat, support- 

 Spinning. } ' 



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 



1 Structure and Habits of Spiders, page 76. 



