176 PROTECTION OF WOODLANDS. 



spines right down to the sheath. In July, when fully grown, the 

 caterpillars descend from their feeding-ground on the tree-foliage 

 for the purpose of entering into the pupal state of rest under the 

 moss with which the ground is usually covered. When this is 

 wanting, they hibernate as chrysalides in the soil itself, scattering 

 themselves over the whole of the area attacked until the following 

 spring again calls them into active life as imagines. The period of 

 pupal rest is therefore of exceptional length, extending over eight 

 months. 



The Pine Owlet-moth or Pine Beauty lives only on Pines, and 

 especially in pole-forests ; but when its reproduction is favoured 

 by warm dry weather it becomes very prolific, and has at various 

 times done very considerable damage over extensive areas, some- 

 times totally destroying pole-forests of Pine amounting to 2000 

 acres in one block (e.g., Bunzlau town forest in Silesia, 1884). 



Among birds and animals this insect has a great many natural 

 enemies, which either feed on the almost naked caterpillar, or 

 else on the chrysalides lying unprotected on the soil for about 

 eight months. Such enemies include birds of all descriptions, 

 predatory insects (Carabidw), flies (Tach/inin&), and ichneumon- 

 flies (Ichneumonidx), then swine, badger, hedgehog, and mice. 

 The caterpillars are also extremely sensitive to damp, cold, raw 

 weather, which often kills them off with great rapidity, 1 so that 

 this sensitiveness, coupled with the action of their natural enemi< 

 often effectually suppresses their tendency to numerical increase. 



The herding of swine in the woods is a good practice 

 annihilative measure, as they are particularly fond of tl 

 chrysalides, and know very well how to find them out; wh< 

 any wild-pigs are still maintained, the presence of the insect 

 often be betrayed by examining the vicinity of patches whei 

 they have broken up the soil with their snouts when in quest 

 the pupae. 



In pole-forests that have been attacked, the caterpillars 

 easily be brought down to the ground by shaking the young pol< 

 or tapping older ones with a padded mallet or axe-head (vide 

 61) ; and they can often be killed off in heaps when they 



1 In some of the Pine woods of Northern Bavaria the year 1889 threatened to brinj 

 a plague of these owlet-moths, but suddenly, about the middle of June, nearly all tl 

 caterpillars, which were nearly full-grown by that time, died off, without ani 

 apparent reason being deducible from changes in temperature and weather, parasit 

 or similar intelligible reason. 



