THE PROCESSIONARY AND GIPSY MOTHS. 591 



be imagined that when they approach a nest of the Processionary 

 Moth they are not slow to avail themselves of the opportunity. 

 Indeed, so sure are they of discovering their prey, that Reaumur 

 asserts that he never opened a nest of the Processionary Moth 

 without finding one or more specimens of their rapacious enemy, 

 as many as five or six having been seen in a single nest. They 

 are most voracious creatures, as indeed is evident from their struc- 

 ture ; and, as each grub will eat several large caterpillars in a day, 

 the havoc which is made in the nest may easily be imagined. The 

 caterpillars have no means of defense or escape. They can not 

 leave their home, and they can not kill or expel the intruder. All 

 that they can do is to go out and eat, and come back and be eaten, 

 their numbers ever diminishing, like the companions of Ulysses 

 in the Cyclops' cave. 



But for the exertions of this most useful insect, the ravages of 

 the Processionary Caterpillars would be greatly increased, for the 

 creature does not only eat them while in the larval condition, but 

 feeds upon them after they have become pupas. Sometimes, how- 

 ever, this extreme voracity defeats its own purpose. It occasion- 

 ally happens that a grub of the Calosoma habitually gorges itself 

 to such an extent with Processionary Caterpillars that it becomes 

 fat, unwieldy, and scarce able to move. If, when it is in this con- 

 dition, leaner and hungrier grubs should come across it, they are 

 too apt to seize upon it and devour it in sheer wantonness, even 

 though the nest be full of their legitimate prey. 



Knowing the habits of this grub, a French entomologist, M. 

 Boisgerard, managed very ingeniously to avail himself of its de- 

 vouring capacities. There is a well-known insect, Bombyx dis- 

 par, popularly called the Gipsy Moth, which is very common in 

 France, though scarce in most parts of England. The larva of 

 this moth is destructive to trees, feeding on their leaves, and then 

 retreating to a cunning little hiding-place in some crevice of the 

 bark. Finding that his trees were infested with these caterpil- 

 lars, M. Boisgerard procured a number of female Calosomas, and 

 placed them on the trees. They laid their eggs, and in due sea- 

 son the larvae were hatched. In process of time the destructive 

 grubs increased so much that they ate all the noxious caterpillars, 

 and at the end of the third year the trees were cleared, and the 

 Calosoma beetles had to go elsewhere for a living. 



In England the Calosoma is exceedingly rare, all specimens 

 hitherto captured having been apparently blown over the sea 



