OUR BEETLE FRIENDS 225 



in a regular army that these caterpillars have 

 gained their name of Processional larvae. All 

 day long the caterpillars remain perfectly 

 quiet, closely packed together within the 

 shelter of the nest, but directly the dusk draws 

 on, there is a general stir. Then indeed a 

 strange sight may be witnessed ; a single cater- 

 pillar leaves the nest and begins to ascend the 

 trunk of the tree, in a moment it is followed by 

 another, and this by a third, and then comes a 

 rank of three or four larvae, which in turn is 

 followed by many more, the ranks gradually 

 increasing in their numbers in a wonderfully 

 regular manner, until at last the rear of the 

 column issues in rather confused order from 

 the nest. After they have devoured as much 

 foliage as they can eat, the army forms up once 

 more in precisely the same order and marches 

 off home. There is the same formation should 

 the host migrate from one branch to another in 

 search of food. When full grown, the larvae do 

 not separate, but gradually increase the thick- 

 ness of the walls of their common web with the 

 aid of their moulted skins, and then each larva 

 makes for itself a cocoon within which to pass 

 through its final transformations. It is during 

 their evening peregrinations that these cater- 

 pillars fall hapless victims to the Calosoma 

 Beetle and its larvae, which attack and devour 

 them in large numbers. Indeed, but for the 

 activity of this beetle in both the larval and 

 adult stage of its life, in preying upon the 

 Processionary Caterpillars, they would quickly 

 strip the oak trees of every vestige of foliage. 



