sider size, for they are the largest of the Arachnida, some tropical forms at- 

 taining a body length of eight inches. The native species occur in the southern 

 and western states. Their large, crab-like claws and the long abdomen end' 

 ing in a poison sting identify them at once. Like many other animals possess- 

 ing poison glands, they are not aggressive, but use their poison weapons only 

 in self defense. They are nocturnal and carnivorous, feeding on insects and 

 spiders. Unlike most of the other Arthropoda, they bring forth living young, 

 which are carried for some time attached to the body of the mother. 



The harvestmen or daddy-long-legs are common all over the world. They 

 spin no webs, as do most of the spiders, although they feed upon insects. Only 

 three pairs of legs are commonly used for locomotion, the first pair apparently 

 serving as sensory appendages or feelers. The ease with which they lose legs 

 is familiar to every country child and may be a defensive mechanism. They have 

 few natural enemies, however, for they excrete an ill-smelling fluid when dis- 

 turbed. In the northern states the eggs are laid in the fall and hatch in the 

 spring into small, white creatures with black eyes. 



The true spiders have two evident body divisions, the cephalothorax or 

 fused head and chest, and the abdomen. Their elaborate webs are sure to at- 

 tract attention even where the animals themselves are overlooked. Not all 

 spiders spin webs, however. An interesting sequence may be arranged, start- 

 ing with the spiders such as the crab and jumping spiders, which spin no webs. 

 Then we may consider those that leave a guide line or safety thread wherever 

 they travel. Other spiders weave silken tubes for retreats or hiding places. 

 Still others extend this tube into a funnel, which functions as a trap for their 

 prey. Some have carried the process further and make elaborate snares. Those 

 of some species are like inverted bowls and catch insects as they fly upwards. 

 Other webs are concave and are hung where aphids and other insects may drop 

 into them. The orb spiders make the most attractive and geometrically perfect 

 webs. 



In addition to providing shelter and ensnaring food the silk often serves 

 as a swing or even as a balloon and aids in the dispersal of spiders. Some are 

 known to have landed with their delicate parachutes on ships far out at sea, and 

 the presence of common spiders on widely scattered islands may be attributed to 

 this efficient method of travel. Several attempts have been made to utilise 

 spider silk for spinning. The silk, although much finer than that of the silk- 

 worm, retains its elasticity well and can be woven into cloth. The chief argu- 

 ment against its use lies in the difficulty in feeding spiders and in keeping many 

 peaceably together. The silk, because of its fineness, is utilized for cross hairs 

 in several types of surveying instruments. 



Contrary to general impressions the spiders are not naturally aggressive 

 to man and only a few of them will bite, even when roughly handled. Only 

 one of the common spiders, the black widow, is dangerously poisonous. This 



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