366 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



and, when running in autumn among the dull yellowish, decaying grass 

 and rushes, looks much larger than it really is. All of a sudden one loses 

 sight of it, and unless he is aware of its habits, is puzzled to know what 

 can have become of it ; but there it is close by, stretched out at full length 

 along the similarly colored stem of grass or rush, with its first and second 

 pairs of legs put forward in a straight line, and its third and fourth pairs 

 stretched in the same way backwards, so as to be scarcely distinguishable 

 from the stem itself. ^ 



In the case of Tetragnatha the mimicry of the twig on which she lies 

 appears at first sight very striking. I have no disposition to undervalue 

 the character or protective benefit of this mimicry. But it must 

 ^ . be remarked that, in point of fact, she simply assumes the posi- 



tion which she habitually takes when hanging on her web. Both 

 tills genus and Uloborus stretch themselves out upon the central part 

 of their orb, or upon a string suspended from it, with their feet ap- 

 proximated in precisely the attitude above described as taken by them 

 when they stretch along the under part of a branch. We are therefore 

 compelled to inquire how far this attitude of Tetragnatha may be a de- 

 li)>erate attempt to shield herself, and how far it is the natural result of 

 habit prompting her, when attempting to screen herself, to drop into the 

 form natural because most connnon to her. The value of the form need 

 not be questioned, but in considering its origin we are required to con- 

 sider the habitual attitude of ,the spider upon her web as well as the atti- 

 tude of mimicry upon a twig during her occasional excursions. Some 

 other spiders have the habit of stretching themselves like Tetragnatha 

 upon foliage and twigs, as, for example, the Orchard spider, although not 

 to the same extent as Tetragnatha. (Plate III., Fig. 6, above.) 



The ordinary, or at least the common, position of Epeiroids, when rest- 

 ing outside their nests or snares, is to draw up the legs so that the two 

 front pairs are humped up above the head and are nearly in a 



„ ' plane with each other and the sv)ider's face. The hind legs are 

 ing Knots \ . ^ ■ i i r i . i 



drawn up agauist the abdomen, ihe sjnder thus forms a little 



roundish bunch and as thus seen is not unlike one of the knots, warts, 

 or excrescences frequently seen upon plants. This habit universally pre- 

 vails among spiders, and one who follows their actions for a little while 

 will be certain to observe it. Thus they remain perfectly still, and at a 

 casual glance might be taken for a knot or other excrescence upon the 

 bark of a tree or plant, as in the case of Epcira strix, represented Plate 

 III., Fig. 4. 



The mimicry of a wart, knot, or liud, or other natural irregularity, 

 would seem to be quite as useful as the special mimicry of Tetragnatha, 

 since it would be as likely to deceive the eye of a prowling enemy. In 



' Cambridge, Spiders of Dorset. 



