ANIMALS WITH JOINTED FEET-THE ARTHROPODS 



247 



Fig. 11-46. American tarantula (Eurypelma), one of the 

 largest of all spiders. They are harmless if properly 

 handled and live to a ripe old age in captivity. This 

 specimen is 26 years old (estimated) and has been 

 in the possession of Mr. Robert Baird for 22 years. 



The dorsal view is shown in upper picture. Note 

 the eight pairs of legs and the "hairy" body. 



In the lower picture, the ventral view, the large 

 powerful nippers are seen which are used in sting- 

 ing the prey. The spinnerets can be seen on the tip of 

 the abdomen. The silk glands lie just inside the 

 abdominal cavity and the secretion is forced out 

 through the tiny openings, solidifying into thread 

 when it contacts the air. 



The food of this spider is other arthropods, usually 

 insects, although it will kill a small bird and feed 

 on it. Its sting is relatively harmless to man. 



these the first group is the most important. 



The acquired fear of spiders and scor- 

 pions is almost as characteristic among peo- 

 ple as is the fear of snakes. In either group 

 of animals, however, only a small number 

 is actually harmful to man; most of them 

 benefit him in one way or another. The 

 spiders, for example, feed almost entirely 

 on insects, many of which are pests to man- 

 kind; their efforts in keeping the insect pop- 

 ulation down is probably considerable. The 

 spider's persistence has become legendary 

 through the story of Robert Bruce and the 

 spider. 



Passing through the woods or sometimes 

 in the open in the late summer, all of us 

 have no doubt had to brush cobwebs from 

 our brows. These are made by the famous 

 "ballooning spiders," which are recently 

 hatched spiders that seek some high place 

 from where they can float, clinging to their 

 tiny thread. Even in the most feeble breeze 

 these tiny spiders float great distances, 

 sometimes far out to sea. It is their method 

 of dispersal, which makes it possible for the 

 species to find new and fertile places to 

 hunt for food. Others build very delicate 

 webs in which flying insects are captiu'ed 

 and sucked dry by the owner of the web. 

 Watching a spider spin such a web is in- 

 deed a fascinating adventure. Other spiders 

 chase and catch their prey; still others leap 

 upon it and kill it by piercing the body with 

 their sharp nippers (Fig. 11-46) and inject- 

 ing a small quantity of poison that simply 

 paralyzes the insect, until it is consumed by 

 the spider. Such a paralyzed insect may stay 

 in a fresh condition for a long time — a kind 

 of room-temperature refrigeration. Some of 

 the tarantulas may feed voraciously when 

 food is available, but when it is scarce they 

 may go for months without food and remain 

 in good health. Although most spiders live 

 only a year or so, tarantulas have been kept 

 in captivity for as long as 26 years. 



The bite of most spiders is harmless, even 

 the bite of the large tarantula being no 



