PROCESSION ARY CATERPILLAR S 147 



alternately. In the first movement, the spinneret, 

 situated in the lower lip, glues the thread to the road 

 that the procession is following; in the second, the 

 spinneret lets the thread run out while the cater- 

 pillar is taking several steps. Then the head is 

 lowered and lifted again, and a second length of 

 thread is put in place. Each caterpillar that follows 

 walks on the threads left by the preceding ones and 

 adds its own thread to the silk, so that in all its 

 length the road passed over is carpeted with a silky 

 ribbon. It is by following this ribbon conductor 

 that the processionaries get back to their home with- 

 out ever losing their way, however tortuous the road 

 may be. 



"If one wishes to embarrass the procession, it suf- 

 fices to pass the finger over the track so as to cut 

 the silk road. The procession stops before the cut 

 with every indication of fear and mistrust. Shall 

 they go on? Shall they not go on? The heads rise 

 and fall in anxious quest of the conductor threads. 

 At last, one caterpillar bolder than the others, or 

 perhaps more impatient, crosses the bad place and 

 stretches its thread from one end of the cut to the 

 other. A second, without hesitating, passes over on 

 the thread left by the first, and in passing adds its 

 own thread to the bridge. The others in turn all do 

 the same. Soon the broken road is repaired and the 

 defile of the procession continues. 



"The processionary caterpillar of the oak marches 



in another way. It is covered with white hairs 



turned back and very long. One nest contains from 



n to eight hundred individuals. When an expe- 



