156 Processionary Caterpillars 



soft surface, which took us on to the verv summit of the hill and 

 ended in a large, circular expansion protected b)- a low stone parapet. 

 A batter}^ mounted here would command the whole valley in which 

 Sospel hes, and the adjoining Italian frontier. The ground was 

 lightly covered with snow and it was bitterly cold, but we were 

 fully repaid for our discomfort by the unspeakably beautiful panorama 

 that lay unfolded below us. The fertile valley stretched awav for 

 mile after mile, bathed in brilliant sunshine, and the mountains 

 appeared heavy and dark against a background of leaden snow- 

 clouds. 



It was here that we met with our hairy caterpillars. On this 

 high ground, firs — Austrian pines I think — were the only trees to be 

 seen. They were small trees from 10 to 30 feet in height, and 

 one noticed at once that the great majority were in very bad health ; 

 some nearly dead, others showing irregular patches of brown amid 

 the green foliage, and hardly one that seemed to be in \'igorous health. 

 Almost all these trees had one or more enormous grey cocoons 

 attached to their branches — attached is perhaps not a good word, 

 for the cocoons were built right round the terminal or lateral shoots 

 of a branch so as to include entirely the shoot in the web. In colour 

 they were dirty grey, and in size from that of an orange to that of 

 a coco-nut, and even larger. They were remarkably conspicuous. 

 Neither insect, bird, mammal, nor even the unintelligent human being 

 could fail to see them from afar. The large, pale, smoke-coloured 

 web stood out in marked contrast to the green foliage of the fir, 

 or to the brown colour of the dead fir needles where the cocoon- 

 selected branch had died. 



These enormous cocoons are, I believe, made obvious iiiten- 

 tionally. They are intended as warning signs — notice-boards that 

 trespassers will be prosecuted. They are danger-signals, which are 

 perfectly well understood by all would-be spoilers, and they are left 

 alone. 



We hadn't walked far up the soft road before we fell in with 

 what to me was a most extraordinary sight. A long line of cater- 

 pillars moving slowly along, head to tail, in Indian file. The first 

 procession we met was about twenty feet long, but was far from 

 complete when we found it ; twenty feet of caterpillars were in line 

 and on their travels, but there remained nearly as many again at 

 the base, waiting to take their place in the procession. 



The front of the line terminated in a single caterpillar. Tracing 

 them backwards, we found that the other endf, the base, terminated 

 in a seething mass of caterpillars, rolling about in a saucer-like 

 depression in the road, such as might have been made by the 

 impression of a hoof. 



Each caterpillar's movement was, I suppose, purposeful, and, 

 possibly, each one had a certain definite place to take up in the 

 processionary line ; but to the casual observer, they looked like a 

 basket of eels rolling over and over each other without aim or reason. 



