. Annual report of the Agricultural Experiment Station. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). 232 nets in wliicli it is looped back and forth. And even in the nets where the greater part of the thread is in a spiral there are in most cases a few loops near the lower margin (Fig. 115). Examine the next orb-web you will find and see if it is true in that case. Many of the orb weavers strengthen their nets by spinning a zigzag ribbon across the center. This ribbon is made by spreading apart tiie spinnerets, the organs from which the silk is spun, an
. Annual report of the Agricultural Experiment Station. Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). 232 nets in wliicli it is looped back and forth. And even in the nets where the greater part of the thread is in a spiral there are in most cases a few loops near the lower margin (Fig. 115). Examine the next orb-web you will find and see if it is true in that case. Many of the orb weavers strengthen their nets by spinning a zigzag ribbon across the center. This ribbon is made by spreading apart tiie spinnerets, the organs from which the silk is spun, and which will be described later. Ordinarily the tips of the spinnerets are held close together so that they form a single thread, but by spreading them apart many threads can be spun at once, thus form- ing a ribbon. Some orb weavers are not content with making a simple zigzag band across the center of the net, but w^eave an elaborate bit of lace in this position. Figure 116 is from a photo- graph of the center of the net of one of these spiders, which w^as found near Ithaca. In studying the various kinds of orb-webs one should pay particular attention to the center of the "web; for this part differs greatly in the webs of the different species. There is usually a huh com- 116.—Lace-likehub i .• i ^ i i i -• -n ' , , posed entn-ely oi dry and elastic silk woven m an of ail oro-weo. ^ j j irregular manner ; outside of this there are several tnrns of a spiral thread, which is also dry; this constitutes the notched zone^ a name suggested by the fact that the spiral line is attached for a short space to each radius it crosses, thus giving the line a notched course. In many cases it is here, on the hub and the notched zone, that the spider waits for its prey ; and it is obvi- ous that sticky silk in this place would be objectionable. Between the notched zone and the spiral zone^ the part furnished with the sticky spiral thread, there is a clear space, tlie free zone, cros
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