i 4 4 ARACHNIDANS. 



The spiders possessing but one pair of respiratory sacculi con- 

 stitute the genus of Spinning Spiders (Aranea), so called on 

 account of the perfection of their webs the first named of the 

 race, of course, being Miss Arachne, who was turned into a spider 

 for having challenged Minerva to a spinning-match. These are 

 divided, according to their habits, into 



The Sedentary Arachnidans, distinguished by weaving webs, 

 or, at least, casting out threads in order to entrap their prey, whilst 

 they remain concealed in the vicinity of their snares. These have 

 eight eyes two or four of which are placed in the middle of the 

 forehead, and the rest on each side. Some species, which always 

 walk straightforward, are called 



Rectigrades (Rcctigrada). They weave webs of different kinds, 

 and hence have been divided into several families. 



FIG. 154. THE EYES OF SPIDER. 



The Tube-weavers ( Tubitdes\ or Tapestry Spiders, are celebrated for their 

 ingenuity. The geometric web of the common Garden Spider (Epeira diadema) 

 has been admired in all ages as a wonderful production, elaborate in its con- 

 struction and most effective for its purpose. These nets are composed of two 

 sorts of threads. The framework, which is first formed, consists of straight 

 rays diverging from a centre ; these are not adhesive, but over these the spider 

 then travels, weaving a spiral thread round and round, which is the true net ; 

 for this thread, which is more elastic than the other, is studded all over with 

 minute globules of a gummy substance, by which it is rendered tenacious. 



In Rio de Janeiro the family Epeira is characterized by many singular forms. 

 Every path in the forest is barricaded with the strong yellow web of a species 

 said to make nets so strong as to catch birds. A small but pretty kind of 

 spider lives as a parasite upon every one of these webs ; possibly it is too in- 

 significant to be noticed by the great Epeira, and is, therefore, allowed to prey 

 on the minute insects which, adhering to the lines, would otherwise be wasted. 



