IMPERFECT SOCIETIES OF INSECTS. 



21 



graceful curves of varying figure, thus forming a series of 

 living wreaths, which change their shape every moment : — 

 all move with a uniform pace, no one pressing too forward or 

 loitering behind ; when the first stops, all stop, each defiling 

 in exact military order. 1 



A still more singular and pleasing spectacle, when their 

 regiments march out to forage, is exhibited by the caterpillars 

 of the Processionary moth ( Cnethocampa processionea). This 

 moth, which is a native of France, and has not yet been 

 found in this country, inhabits the oak. Each family consists 

 of from 600 to 800 individuals. When young, they have no 

 fixed habitation, but encamp sometimes in one place and 

 sometimes in another, under the shelter of their web : but 

 when they have attained two thirds of their growth, they 

 weave for themselves a common tent, before described. About 

 sunset the regiment leaves its quarters ; or, to make the 

 metaphor harmonise with the trivial name of the animal, the 

 monks their coenobium. At their head is a chief, by whose 

 movements their procession is regulated. When he stops, 

 all stop, and proceed when he proceeds ; three or four of his 

 immediate followers succeed in the same line, the head of the 

 second touching the tail of the first : then comes an equal 

 series of pairs, next of threes, and so on as far as fifteen or 

 twenty. The whole procession moves regularly on with an 

 even pace, each file treading upon the steps of those that 

 precede it. If the leader, arriving at a particular point, 

 pursues a different direction, all march to that point before 

 they turn. Probably in this they are guided by some scent 

 imparted to the tracks by those that pass over them. Some- 

 times the order of procession is different ; the leader, who 

 moves singly, is followed by two, these are succeeded by 

 three, then come four, and so on. When the leader, — who 

 in nothing differs from the rest, and is probably the cater- 

 pillar nearest the entrance to the nest, followed, as I have 

 described, — has proceeded to the distance of about two feet, 

 more or less, he makes a halt ; during which those which re- 

 main come forth, take their places, the company forms into 



1 Bonnet, ii. 57. 



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