LEPIDOPTERA. 251 



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 jaws 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. The 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 those 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 followed 

 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 one caterpillar coming out of any 

 of the nests, by the opening which is at the top, which would hardly 

 afford space for two to come out abreast. 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 continue 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 takes place in all the neighbouring nests ; all are evacu- 

 ated at the same time." 



One part of Fig. 233 shows the arrangement of the caterpillars on 

 coming out of the nest. These caterpillars are furnished with long 

 hairs, slightly tufted, which come off with the greatest ease, and which 

 if they penetrate into the skin, cause violent itching. In 1865 a 

 number of the alleys of the Bois de Boulogne were shut up from the 

 public in order to save them from this annoyance. These caterpillars 

 construct a covering common to them all, in which they live, and 

 transform themselves therein, each insect making for his own private 

 use a small cocoon. This insect is said to have been found in England, 

 but there is not sufficient evidence to admit it into our lists. 



