1,50 SC(^Rl'rONS, STIDKRS, AXD TICKS 



ones so thai onl)' tlie fittest ones survive to become adults 

 in the spring. 



Forest patlis are often crossed by threads of spider's 

 silk. A spider climbs to the end of a branch and spins out 

 a thread which is caught b}' the L)reeze and wafted across 

 the path, where the end liecomes entangled in a branch on 

 the opposite tree. 



Certain spiders, known as tlie ballooning, or flj'ing spiders, 

 climb to the end of a post or to the tip of a plant and spui 

 silk into the air which is caught and wafted away by the 

 breeze. When enough is spun to support the spider, it 

 lets go and is l)orne away l)y the currents of air. These 

 spiders travel long distances in diis manner, as shown by 

 the fact that they have Ijccn seen floating througli the air at 

 sea far from land. 



The spiders that build the irregular wel)s, termed cob- 

 webs, in d^^•clling houses belong to the family of cobweb 

 weavers. They ai-e small spiders witli very slim legs, and 

 there are many differeid- species of them, l-iy far the larger 

 number live in the fields and spin their \\'c)3s on bushes. 



Tho.se webs spun by the spidei's known as orb weavers 

 are marvels of ingenuity and regularity of construction. 

 The webs are common on bushes, fences, weeds, etc. (Fig. 

 88), but are usually given little attention. The outer frame- 

 work of supporting threads is often very irregvilar; but the 

 i-adiating lines are placed at regular intervals from each 

 other, and the spiral is laid on tliese in a I'ogular manner. 



The radii are dry and inelastic, wlule the spii'al thread 

 is sticky and ehistic. Some of the oi'b weavei-s spin a zig- 

 zag band, 01- ribbon, across the center of th(^ well, evidently 

 to strengthen it. Many of the orb weavers are small 

 spiders, but some are large. The funnel web weavers spin 



