. 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. 50 AMERICAN SPIDERS AND THEIR SPINNINGWORK. sp- were uniformly eight, two of which were situated on the inferior surface of the spinneret at a greater distance from the extremity than the rest, and were minute and almost contiguous. It is a fact deserving notice that the spinning spools are not always developed simultaneously on these spinnerets, six, seven, and eight being sometimes observed on one, while five, six, or seven a
. 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. 50 AMERICAN SPIDERS AND THEIR SPINNINGWORK. sp- were uniformly eight, two of which were situated on the inferior surface of the spinneret at a greater distance from the extremity than the rest, and were minute and almost contiguous. It is a fact deserving notice that the spinning spools are not always developed simultaneously on these spinnerets, six, seven, and eight being sometimes observed on one, while five, six, or seven are to be seen on the other. This remark is applicable not to the anterior spinnerets alone, but to the intermediate ones also, which, in mature individuals, are further modified by having the extremities of the terminal joints directed forwards at right angles to their bases. The same condition was observed in a species of Drassus and in Segestria senoculata. It is not improbable, there- fore, that other species, and per- haps all spiders, follow the same law of development. This whole system of liquid silk supply is regulated by the compression of surround- Muscular â , i ⢠i_ . Svstem ^"^ muscles, which act upon the several glands in the manner of the hand when squeezing upon the rubber bulb of a spraying tube. The contents are forced out of the glands in this liquid condition, through the long, delicate ducts, into the hollow spiu- Fic;. 46. Epeira diademate. sp (p), spigot of treeform ning tubcS, wlienCC tllCy isSUC in gland on posterior spinneret; 88 (p), spools of pyriform ⢠i â . .i i ji glands on same. (After Underhill.) X 165. minUtC JCtS tlirOUgh the CXteriOr openings or mouths of the spools. As the i)oints of the si)ools or tips of the spinnerets are approximated, a number of these jets flow together, and hardening instantly upon contact with the air, form the thread or line familiarly known as the spider's web. The excretory ducts, as well as the silk g
Size: 892px × 2801px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
