i 5 2 AMERICAN SPIDERS 



Triangle Spiders. Almost anywhere in the United States may be 

 found the peculiar triangular snare of the spider Hyptiotes, which, 

 because of its small size and retiring habits, is far less familiar than 

 the web it spins. A small creature, rarely more than one sixth of 

 an inch in length, the triangle spider hangs back-downward from a 

 dried twig in its favorite trapping site, and is no more noticeable 

 than a bit of dead wood, a bud, or a piece of bark. The carapace is 

 broad and low; it supports a thick, oval abdomen on which are 

 usually visible slight humps set with a few stiff hairs. Drably 

 clothed in grays and brown, Hyptiotes harmonizes rather well with 

 the dry branches of its home, and affords a striking illustration of 

 close resemblance to environment. All eight eyes are present in this 

 species, but one minute pair is so well hidden in the hair covering 

 that the spider was once thought to have only six eyes. The male 

 ordinarily becomes adult in the early fall, and at that season may 

 sometimes be found near the web of the female, which sex he re- 

 sembles closely except for smaller size. 



Two well-marked species of Hyptiotes occur in the United 

 States and Canada. The common species in our eastern states is 

 Hyptiotes cavatus, Hentz's triangle spider; while the boreal tri- 

 angle spider, H. gertschi, is abundant in the western part of the 

 country, and largely replaces the other species in eastern Canada, 

 where it occurs as far south as Maine and New York. 



The web of the triangle spider (Text Fig. 4, B) is best under- 

 stood by comparing it, as did Professor Bert G. Wilder in his early 

 studies of cavatus, to an ordinary pie. The orb of Uloborus is an 

 entire pie; that of Zilla, one of our typical orb weavers, is a pie with 

 a piece cut out of it; and that of Hyptiotes is the missing piece. This 

 triangular web consists of a fifty-to-sixty-degree sector with radii 

 twelve to twenty inches long. It invariably consists of four rays of 

 dry silk, across which are laid down ten or more viscid lines of 

 hackled band that correspond to sections from the spiral line of an 

 orb web. The four rays are attached to an arc line tied to twigs, and 

 converge near a point on a single bridge line fastened to some nearby 

 object. 



The spinning of the web, often accomplished during the early 

 hours of the evening, is a most interesting process; and the details 

 corroborate the belief that its structure is derived from the uloborid 

 orb web. The first line is a bridge from the resting site of the spider 

 to an adjacent dried twig. It is customary for Hyptiotes to place 

 the bridge line by hand, moving around the periphery of her hunt- 



