j 6 THE STUDY OF INSECTS 



easy matter for the spider to stretch its other lines where it wishes them. 

 In doing this it fastens a thread to one point, and then walks along to 

 some other point, spinning the thread as it goes, and holding it clear of 

 the object on which it is walking by means of one of its hind legs. When 

 the second point is reached the thread is pulled tight and fastened in 



place. 



After making the outer framework the radiating lines are formed. A 

 line is stretched across the space so as to pass through the point which is 

 to be the center of the orb. In doing this the spider may start on one 

 side, and be forced to walk in a very roundabout way on the outer frame- 

 work to the opposite side. It carefully holds the new line up behind it as 

 it goes along, so that it shall not become entangled with the lines on 

 which it walks; one or both hind feet serve as hands in these spinning 

 operations. The spider then goes to the point where the centre of the orb 

 is to be, and fastening another line there, it walks back to the outer 

 framework, and attaches this line an inch or two from the first. In this 

 way all of the radiating lines are drawn. The next step is to stay these 

 radii by a spiral line which is begun at the center, and attached to each 

 radius as it crosses it. The turns of this spiral are as far apart as the 

 spider can conveniently reach, except at the center of the w r eb. All of the 

 threads spun up to this stage in the construction of the web are dry and 

 inelastic. The spider now proceeds to stretch upon this framework a 

 sticky and elastic line, which is the most important part of the web, the 

 other lines being merely a framework to support it. In spinning the 

 sticky line the spider begins at the outer edge of the orb, and passing 

 around it fastens this line- to each radius as it goes. Thus a second spiral 

 is made. The turns of this spiral arc placed quite close together, and the 

 first spiral, which is merely a temporary support, is destroyed as the 

 second spiral progresses. Figure 3 1 represents a web in which the second 

 spiral is made over the outer half of the radii. In this figure, aa repre- 

 sents the temporary stay-line; 66 the sticky spiral; and cc the fragments 

 of the first spiral hanging from the radii. 



The orb weavers arc 1 three-clawed, eight-eyed, sedentary spiders. The 

 tarsi are more or less clothed with hairs; but they lack the comb charac- 

 teristic of the Theridiidae. They are fairly common, many of our large 

 garden spiders being common representatives. 



Family Thomisid^; 

 The Crab Spiders 



There arc certain spiders which are called crab spiders, on account of 

 the short and broad form of the body, and the curious fact that they 

 can walk more readily sidewise or backward than forward. 



These spiders spin no webs, but lie in wait for their prey. They live 

 chiefly on plants and fences, and in the winter hide in cracks and under 

 stones and bark. Most of the species are marked with gray and brown, 

 like the bark upon which they live. Some species conceal themselves in 

 flowers, where they lie in wait for their prey. These are brightly colored, 

 like the flowers they inhabit; so that insects visiting flowers may alight 

 within reach of a spider before seeing it. 



In this family the legs arc turned outward and forward more than 



