Kew : Snares or Snap-nets of Triangle Spiders. 201 



in regular loops ; according- to McCook there are three strands, 

 viz.: the central smooth thread, and two curled thread's, the 

 latter crossing and recrossing above and below, and forming 

 loops. The curled threads are not made separately and attached 

 to an already existing thread as in Amaurobiidae ; both smooth 

 and curled threads being, in the present case, spun at the same 

 time. 



The spider appears to prefer to construct its snare just 

 before day. To its early habits in this respect Wilder (who 

 kept many individuals in his house) attributes his failure to 

 observe the whole process ; twice he attempted to sit up all 

 night, but the spiders appear to have commenced work just as 

 he fell asleep in the morning. The construction of the warp of 

 the snare — the radii, trap-line, and base-line — w r as never wit- 

 nessed by this observer. The original line, as he supposes, 

 is doubtless air- 

 carried. As to the 

 subsequent steps, 

 however, Wilder 

 refrains from specu- 

 lation ; and, refer- 

 ring to Figs. 4-6, 

 merely states that 

 in some way or 

 other the spider 

 connects with the 

 original line (OB) 

 four others, con- 

 stituting the base- 

 line (BB), and the three lower radii (i?" R m R im ), which latter 

 are joined to the base-line at F, G, and H. The upper radius 

 is formed, he adds, by the central part of the original line ; 

 and the three others unite with it at A, the apex of the triangle. 

 McCook also failed to see the construction of these lines, and 

 the order in which they are spun, by Hyptidtes cavatus, has not 

 been observed, as far as the writer knows, by any naturalist. 

 McCook, however, after a careful study of a number of snares, 

 lias made suggestions on this point, which may be here repeated. 

 He thinks it probable that the spider first spins a thread repre- 

 sented, in Fig. 3, by the dotted line PH. She may then proceed 

 to attach to this line, say at A, another thread, carrying it along 

 PH to the place of attachment B, thence up the branch or other 

 object to C, where the carried thread would be drawn taut and 



1900 July 2. 



C 



Fig- 3« — Diagram illustrating- the possible manner in 

 >vhich Hyptiotes cavatus makes the framework of its snare. 

 After McCook, American Spiders and their Spinningwork, I. 

 (1880), p. 183, Fig. 171. 



