THE TRIANGLE SPIDER: THE ORB SECTOR. 187 



character of the spiral can only be satisfactorily determined by taking it 

 upon a suitable frame and observing it under the microscope. 



The spiral lines, where they cross the two interlying radii, are not con- 

 tingent to the radius at one and the same point, but present precisely the 

 appearance of the concentrics in the notched zone of a common full orbed 

 snare. The entire snare of Hyptiotes is thus notched, and in this respect 

 it corresponds with the domed orb of the Basilica spider as I have de- 

 scribed it. 



The length of the snare proper varies a good deal. I have measured 



one five and a half inches in length, another two and a half, and another 



thirteen inches, measuring from the apex to the base line. The 



spiral space itself will measure two and a half inches, three and 



m OTI ^ 



three-fourths inches, rarely more, often less. The length of the 

 base line, which represents the width of the snare at the open or widest 

 part of the triangle, also varies much. I have measured one twenty-six 

 inches hi length, the longest of which I have any note. The radii are 

 not separated from each other by equal spaces at their points of attach- 

 ment to the base line. For example, one 

 snare measured two inches in the upper 

 space, between the first and second radii; 



111 the middle Space, One and One-fourth ^^ 178 - Hyptiotes' spiral armature, greatly 



1 magnified. The regular curls of the floccn- 



ineh ; ill the lower Space, One and One- lent thread are broken up and hang irreg- 



fourth inch. At the point nearest the apex, ularl y- 



where the spiral lines terminated, the width across the snare between the 



two outer radii was three-fourths of an inch. 



The distance from the apex of the triangle to the point where the 

 original line is attached I have called the trapline, and this also varies in 

 length. I have the following measurements : One and one-fourth inch, one 

 and one-half inch, one and six-eighths inch, two and one-half, five, and 

 thirteen inches. The snare drawn at Fig. 169 gave the following measure- 

 ments : trapline, two and a quarter inches ; number of spirals, fourteen, 

 separated from each other by distances varying from one-eighth to one- 

 fourth of an inch ; the spiral space, two and a half inches long ; distance 

 across the web at the origin of the spirals (the point nearest the trapline), 

 two inches ; distance across the web at the termination of the spiral system, 

 four and one-half inches. The three radial openings measured at the base 

 line respectively, two, one and a half, and one and three-fourths inches. 



A fine large snare spun by a male Hyptiotes gave the following meas- 

 urements : number of spirals, twenty-three and twenty-two ; the spiral space 

 occupied three and three-fourths inches in length; the distance across the 

 snare at origin of the spiral space, one inch and five-eighths; distance 

 straight across a, the end of spiral space, five and one-half niches. From 

 the point of the triangle to the origin of the spiral space was two inches. 

 There was a quite long trapline, about thirteen niches. The base line of 



