1 66 



THE GUIDE TO NATURE 



indeed, that it will be quite out of the 

 question to touch upon it in as short an 

 article as this. 



At different times I have photo- 

 graphed quite a number of our var- 

 ious species of spiders, as the Argiope 

 or garden spider, some of the vagrant 

 spiders, tarantulas, the triangle-spider 

 and several others. Two of these are 



As we all know, spiders are noted 

 for the webs or nests they build, some 

 of which are very curious, while others 

 are extremely beautiful. A spider's 

 spinning apparatus is one of the most 

 wonderful animal structures in all na- 

 ture. As stated above, it consists of 

 the spinnerets which occur ventrally at 

 the extremity of the abdomen. The 



~**W!^ 



•jLJSS 



Fig. 2. A vagabond spider with silk sac holding eggs or yourg. Figures reproduced from photographs 



from life by Dr. R. W. Shufeldt. 



reproduced here with the view of show- 

 ing what excellent subjects they make 

 for the camera. In Figure i, we have 

 the well-known and common orb-web 

 spinning garden spider Argiope, and in 

 Figure 2, one of the vagabond or run- 

 ning spiders of the genus Lycosa. It is 

 seen to be carrying its young in a ball 

 spun from its web. 



It will be noted that these spiders 

 have four pairs of legs, whereas insects 

 have but three ; moreover, the eyes in 

 these spiders are what we call simple, — 

 they are compound in all true insects. 



There are many differences between 

 spiders and insects ; yet they have some 

 things in common. For example, both 

 have two pairs of jaws with associated 

 parts; both breathe through spiracles, 

 and both have in their bodies their an- 

 nular plan of structure. Spiders are 

 hatched from eggs and so are many 

 species of insects, and both moult at 

 various stages during their growth. 



receptacle holding the fluid silk is in- 

 ternal, and the latter hardens as soon 

 as it comes in contact with the air. 

 There may be one or two pairs of 

 spinnerets, each being supplied at its 

 end with sometimes as many as a cou- 

 ple of hundred minute tubes, through 

 which the threads pass. By drawing 

 them together, the spiders can spin a 

 thread ; or by having" them diverge, 

 spin a flat ribbon, such as we see zig- 

 zagging" down from the center of the 

 orb-web of the garden spider, here 

 shown in Figure 1. A single thread 

 is sometimes so fine that it will require 

 good eyes to see it, yet it is composed 

 of some hundreds of fine silken threads, 

 each requiring the use of a powerful 

 microscope to discern. 



One can take away from a spider its 

 entire supply of silk; when this hap- 

 pens, and it is allowed to escape, it gen- 

 erally robs some weaker one of its al- 

 readv constructed web. 



