. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. THE TRIANGLE SPIDER : THE ORB SECTOR. 183 Making the Makiug the frame of the Triangle spider's snare. The mode of spinning the foundation lines or frame has never been observed, as far as I know, by any naturaHst. A careful study of a number of webs, however, has led me to con- clude that it is spun as follows: In the first place, the spider stretches between two points a sin- gle line, which we may rep- resent by the d
. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. THE TRIANGLE SPIDER : THE ORB SECTOR. 183 Making the Makiug the frame of the Triangle spider's snare. The mode of spinning the foundation lines or frame has never been observed, as far as I know, by any naturaHst. A careful study of a number of webs, however, has led me to con- clude that it is spun as follows: In the first place, the spider stretches between two points a sin- gle line, which we may rep- resent by the dotted line, PB, in Fig. 171. She then proceeds to attach to this line, say at the point A, another thread, which is carried along the original line, PB, to the place of attachment, B. Thence up the branch or other object to C, where the carried line is drawn taut and fastened. There is thus produced the line AC, and the original foundation line having been drawn upward by pulling upon AC, has assumed the curved form of AB. The two outer radii of the snare are thus in place. Now the spider drops from the point CB, carry- ing with her a tliread, \vhich is attached at B, and becomes thus the base line of the triangle CABC. Proceeding along the line BA, carrying with her a thread as before, she makes another attachment at E, returns upon her course to B, and thence upward to E, on the base line where the carried thread is straightened, fastened, and the third radius, EE, completed. In a similar way the fourth radius, DD, is stretched. This, of course, does not express the exact order in every case, but the general method. It will be observed that these radial lines do not meet in a com- mon point. This is in- deed contrary to most published descriptions of the appearance of the snare. For example, Thorell speaks of these threads in the net of Hyptiotes paradoxus as forming " equal angles with the original thread, and each ; i Em- erton speaks of the apex as " t
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
