. 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. 26 AMERICAN SPIDERS AND THEIR SPINNINGWORK. words, the female is twenty times as long and thirteen hundred times as heavy as her partner.' Dr. Vinson ^ strikingly represents this disparity of size in the species Nephila nigra (Vinson), wliich is here presented, (Fig. 6), with botli sexes natural size. A full grown female of our Basket Argiope bears about the relative proportion to the size of her male, of a horse to a large dog
. 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. 26 AMERICAN SPIDERS AND THEIR SPINNINGWORK. words, the female is twenty times as long and thirteen hundred times as heavy as her partner.' Dr. Vinson ^ strikingly represents this disparity of size in the species Nephila nigra (Vinson), wliich is here presented, (Fig. 6), with botli sexes natural size. A full grown female of our Basket Argiope bears about the relative proportion to the size of her male, of a horse to a large dog. The largest female Argiope measures in body length one inch, in spread of legs three inches. Her abdomen is thick in pro- portion. A male has a body length of one-fonrth inch, the spread of legs being one inch and a quarter. Fig. 14 will show the relative body lengths and sizes of the sexes of Argiope cophinaria. This disproportion, however, in the size of the sexes is not universal. In some species, as will be found by a reference to the plates in Volume III., the difference is slight, and, indeed, is sometimes on the side of the male, even among Orbwcavcrs, as in tlie case of Epeira strix. Moreover, the males have relatively longer and apparently more powerful legs than the female. The increased length must be serviceable in the i)reliminary courtship, when the males stand off and solicit or test the feeling of their mates by touches of the fore feet. These features are also beneficial in clasping their mates during amatory em- brace, and must add to their muscular vigor both in conflict and retreat. This difference in the legs, I have no doubt, fully compensates for difference in body size in the case of many species. Especially is this true in the case of the Wan- derers, with the exception, j)crhai7s, of some of the Thom- isoids. Moreover, the legs of some Orbweavers are armed with formidable weapons in rows of strong spines arranged Fi(i. 7. Tibial spines, aloug the inu
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
