ia 
ae CU ee 
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- 
seribed 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 
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 in 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 ~t 
space, between the first and second radii; 
in the middle space, one and one-fourth F' 178. Hyptiotes’ spiral armature, greatly 
magnified. The regular curls of the floccu- 
inch; in the lower space, one and one- ent thread are broken up and hang irreg- 
fourth inch. At the point nearest the apex, “®"- 
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 fivye-eighths; distance 
straight across a, the end of spiral space, five and one-half inches. From 
the point of the triangle to the origin of the spiral space was two inches. 
There was a quite long trapline, about thirteen inches. The base line of 
Dimen- 
sions. 
