64 



SPIDERS 



[CH. 



A little later in the summer the appearance of 

 a troop of wolf-spiders has undergone a marked 

 change ; almost every individual will be found 

 burdened with a circular bag of eggs attached firmly 

 to its spinnerets, and carried about with it in all its 

 wanderings. 



Fig. 7. Wolf-spiders ; A, with egg-cocoons ; B, with young on its back. 



The "cocoon' is worth examination. It is a 

 rather flattened sphere, with an equatorial line round 

 it, giving the effect of two valves an upper and a 

 lower. The operation of making it has very seldom 

 been observed, because it takes place in a closed 

 retreat constructed for the purpose. McCook was 

 fortunate enough to see something of it in the case 



