May, 1920] Studies in Food of Spiders 217 



MANNER OF CAPTURING PREY. • 



Spiders are distinctly carnivorous creatures. They feed 

 chiefly on insects but some species are known to feed on fish, 

 birds, toads, frogs and crustaceans. Spiders are also cannibals 

 and do not hesitate to devour weaker members of their own or 

 other species. 



They are extremely voracious and will eat a great quantity 

 of food in a short period of time. They are also able to endure 

 long fasts. I kept one alive in a box nearly three months 

 without food. Its death at the end of that time was probably 

 due not to starvation but to the season of the year as it will be 

 remembered that most spiders die in the fall. 



The most primitive way of spiders capturing their prey is 

 seen in the Lycosidae and Attidag. These spiders never construct 

 any snares but wander around in the grass or under stones in 

 search of their prey which they capture by pouncing upon it 

 from the rear. The struggle for existence is severer and as a 

 result these spiders as a rule are not as numerous as web- 

 building species. 



Another class of spiders to which the genus Misumena 

 belongs lie in wait for their prey on plants and flowers. They 

 depend chiefly on protective resemblance to help them in cap- 

 turing their prey and remain immovable until some unsuspect- 

 ing insect walks into their jaws when they close in on it. 



By far the larger number of spiders procure their prey by 

 means of a snare. These spiders remain near or on this snare 

 constantly and capture a great number of insects often a great 

 many more than are used for food. These snares or webs present 

 a great variety of forms, ranging from a small flat sheet on the 

 surface of the ground to the large orbicular webs sometimes two 

 feet or more in diameter built vertically in grass, weeds or 

 shrubs. In giving determinations in this paper we have for 

 the most part given what the spider captured and not what it 

 actually ate. It will be seen that considered from an economic 

 standpoint the value of the spider ought to be rated by the 

 insects it destroys and not by what it eats. 



There is still another class of spiders which feed on what 

 has been captured by other spiders and are called commensal 

 spiders. Most of these are small spiders and relatively unim- 

 portant from an economic standpoint. 



