WEB-SPIDERS. 



231 



captured. It slings up, moreover, a string of cocoons, extending across the web, 

 and at one extremity of the line, or amongst the dried carcases of flies, the 

 spider takes its stand and harmonises so well in shape and colour with its surround- 

 ings as to be practically indistinguishable amongst them. Even more interesting 

 is Hyptiotes, which frequents pine trees, and is 

 a small thick-set little species almost invisible 

 on the bark. It spins a web, triangular in out- 

 line, with anchoring threads passing from each 

 of the angles to surrounding objects, and the 

 triangular space filled in with cross-lines running 

 parallel to the shortest side, and traversed in 

 the middle by a single thread running from the 

 apex to the base opposite. Taking up its position 

 on the long anchoring thread which passes from 

 the apical angle, and close to its point of attach- 

 ment to the branch, the spider pulls in the 

 thread so as to draw the whole net taut, coiling 

 up the slack line between its front and hind-legs. 

 The instant a fly strikes the net, the spider 

 loosens its hold of the line, when the snare 

 springs forward with a jerk, still further entang- 

 ling the prey by bringing other threads into 

 contact with it. If necessary, the net is snapped 

 more than once, and when the spider feels that 

 the insect is enveloped, it crawls leisurely along 

 the web to devour it. 

 Europe and North America. 



AN ORB-SPINNER (Tetragnatha extensa) AT 



EEST IN ITS SNARE. 



The genus is common to 



Arrangement of eyes shown above. 



The other members 



of this tribe belonging to the family Argiopidce have no cribellum nor calamistrum. 

 Their webs vary in form, but are mostly of the orb type, consisting of straight 

 threads radiating from a centre to the foundation lines, which are stretched from 



one point of support to another, and of a spiral line 

 passing from the centre to the circumference, affording 

 support to the radial lines and partly filling in the 

 spaces between them. The spiral line is the principal 

 part of the web involved in the capture of insects, many 

 of its strands being covered with a series of gummy 

 drops like beads on a string, which greatly hamper the 

 movements of a captured insect. The presence and 

 position of an insect in the web is perceived solely by 

 the delicate sense of touch in the spider's feet, and for 

 this reason the spider either takes up its stand in the 

 centre of the web, where its eight legs can command all 

 the radii, or else beneath some leaf at the end of a long 

 thread passing from the centre to its place of concealment. In cases of danger the 

 spiders either drop to the ground by a thread, or, seizing the web with the tips of 

 their feet, start spinning the body round and round in circles and causing the web 



COMMON CROSS SPIDER, Araneus 

 diadema (nat. size). 



