Archive image from page 344 of American spiders and their spinning. 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 CUbiodiversity1121211-9742 Year: 1889 ( THE GENESIS OF SNARES. 345 nearly approaches, in the habitual form of its snare, that form which, as I have shown, incidentallj' results from the long use of Theridium's web of intersecting lines. The step is not a large one by which we may conceive the snare just described to be transformed into that of the dome shaped web of Linyp
Archive image from page 344 of American spiders and their spinning. 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 CUbiodiversity1121211-9742 Year: 1889 ( THE GENESIS OF SNARES. 345 nearly approaches, in the habitual form of its snare, that form which, as I have shown, incidentallj' results from the long use of Theridium's web of intersecting lines. The step is not a large one by which we may conceive the snare just described to be transformed into that of the dome shaped web of Linyphia marginata, or the bowl shaped web of Linyphia communis. It av!°° only needs, in the former case, a little more downward pressure Dome upon the cords at the edges, and in the latter a little more pressure upon the marginal cords upward, to complete the proc- ess. (Fig. 335.) We may now pass from Lineweavers to Tubeweavers. A glance at the snare of Agalena noevia, for example, as represented in Fig. 215, page 217, and Fig. 336, will show how close is the resemblance between it and the snares of Linyphia already described. Agalena has a sheeted web of open spinningwork, or of close, irregular meshwork, as one may choose to put it, whose weft becomes much thickened in course of time by fre- quent overlaying. It also has the crossed lines extending upward, for the most part, but often downward also, representing the original rude intersecting lines of our sup- posed primitive snare. This retitelarian fea- ture of the web is a most important factor in the daily capture of prey, by signaling their presence to the waiting proprietor; by arresting and trapping them so that they fall upon the sheeted premises beneath; and by actually entangling them. This most highly organized of all the fig. 336. sheeted web and tube of Agalena m , . • 1 .1 ,. , , noevia, woven on a hedge. lubeweavmg species has therefore substan- tially a Lineweaver's snare. To this structure is added the tube,
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