THE PINE PROCESSIONARY 123 



ribbon is dilated sufficiently to make it easy to find; 

 nevertheless, on the homeward journey, it is not picked 

 up without some hesitation. For observe that the cater- 

 pillars when on the march never turn completely; to 

 wheel round on their tight-rope is a method utterly un- 

 known to them. In order therefore to regain the road 

 already covered, they have to describe a zig-zag whose 

 windings and extent are determined by the leader's 

 fancy. Hence come gropings and roamings which are 

 sometimes prolonged to the point of causing the herd to 

 spend the night out of doors. It is not a serious matter. 

 They collect into a motionless cluster. To-morrow the 

 search will start afresh and will sooner or later be suc- 

 cessful. Oftener still the winding curve meets the guide- 

 thread at the first attempt. As soon as the first cater- 

 pillar has the rail between his legs, all hesitation ceases ; 

 and the band makes for the nest with hurried steps. 



The use of this silk-tapestried roadway is evident from 

 a second point of view. To protect himself against the 

 severity of the winter which he has to face when work- 

 ing, the Pine Caterpillar weaves himself a shelter in 

 which he spends his bad hours, his days of enforced idle- 

 ness. Alone, with none but the meager resources of his 

 silk-glands, he would find no difficulty in protecting him- 

 self on the top of a branch buffeted by the winds. A 

 substantial dwelling, proof against snow, gales and icy 

 fogs, requires the cooperation of a large number. Out 

 of the individual's piled-up atoms, the community obtains 

 a spacious and durable establishment. 



The enterprise takes a long time to complete. Every 



