156 SPIDERS 



Much of the adventure and risk in the Hfe of the spider is 

 crowded into the first few days of freedom when the young spider- 

 lings, having first left their egg sac, climb over the stems of plants 

 and up the leaves of grasses, stringing their threads as they go. 



Wind ^ 



Fig. 33. Ballooning by young spiders. 



Soon a tangle of webs springs up, crossing in all directions and 

 covering the vegetation. When the young spider has reached the 

 summit of the nearest promontory — a weed, a bush or a fence — it 

 turns to face the wind, extends its legs so that it appears to be 

 standing on tiptoe and lets air currents carry the silk from its 

 spinnerets. When the friction of the currents against the threads 

 exerts sufficient pull, the spider loosens its hold and usually sails 

 away: at the take oflt, at least, it is dragged backwards. Sometimes, 

 after take-off, the spider climbs rapidly to the middle of its thread, 

 which then sweeps forward and becomes doubled. Less frequently 

 the spider makes a forward start. This method is employed by 

 small spiders which make a weak attachment to a support and 

 allow themselves to be blown outward and upward until the 

 thread snaps near its hold (Braendegaard, 1938). 



The modes of life and the habitats of spiders are most varied: 

 some are wanderers throughout their lives, others are almost 

 entirely sedentary; some live in sunny, airy places, others are 

 found in obscure caverns where the light never penetrates. A 



