LEPIDOPTEEA. 253 



trees, and devour the leaves at the moment of their development. 

 In the evening these caterpillars come out of their common nest, 

 and form a sort of procession ; hence their name Procession Moth. 

 ** I kept some for a little time in my house in the country," says 

 Reaumur. " I brought an oak branch which was covered with 

 them into my study, where I could much better follow the order 

 and regularity of their march than I could have done in the woods. 

 I was very much amused and pleased at watching them for many 

 days. I hung the branch on which I had brought them against 

 one of my window shutters. When the leaves were dried up, 

 when they had become too hard for the teeth of the caterpillars, 

 they tried to go and seek better food elsewhere. One set himself 

 in motion, a second followed at his tail, a third followed this one, 

 and so on. They began to defile and march up the shutter, but 

 being so near to each other that the head of the second touched 

 the tail of the first. This single file was throughout continuous ; 

 it formed a perfect string of caterpillars of about two feet in length, 

 after which the line was doubled. There two caterpillars marched 

 abreast, but as near the one which preceded them as those who 

 were marching in single file were to each other. After a few rows 

 of our processionists who were two abreast, came the rows of three 

 abreast ; after a few of these came those which were four abreast ; 

 then there were rows of five, others of six, others of seven, others 

 of eight caterpillars. This troop, so well marshalled, was led 

 by the first. Did it halt, all the others halted: did it again 

 begin to march, all the others set themselves in motion, and fol- 

 lowed it with the greatest precision. . . . That which went on in 

 my study goes on every day in the woods where these caterpillars 

 live. . . . When it is near sunset you may see coming out of any 

 of their nests, by the opening which is at its top, which would 

 hardly afford space for two to come out abreast, one caterpillar. 

 As soon as it has emerged from the nest, it is followed by many 

 others in single file ; when it has got about two feet from the nest, 

 it makes a pause, during which those who are still in the nest con- 

 tinue to come out ; they fall into their ranks, the battalion is 

 formed ; at last the leader sets off marching again, and all the 

 others follow him. That which goes on in this nest passes in all 

 the neighbouring nests ; all are evacuated at the same time." 



