3i 8 Studies in Forestry [CHAP. xiv. 



(species of Turdus\ Rooks ( Corvus frugilegns), the Stannel- 

 hawk (Tinnunculus alaudarius\ and Wasp-buzzards (Perm's 

 apivorus\ Woodpeckers (species of Picus\ Sparrows (Passeres) 

 and Finches (Fringillidae\ Crows or Ravens (Corvus corax\ 

 Jackdaws (Monedula turrium) and Larks (Alaudidae\ which 

 are only of minor utility in this manner. 



C. Among Insects. 



The class of useful forest insects is, on the whole, of consider- 

 ably more importance in keeping a check on the abnormal 

 increase of injurious kinds than either mammals or birds. 

 They comprise not only the various predatory species which, often 

 both as larva and imago, prey on the ova, larvae, pupae, and 

 imagines of noxious insects, but also the parasitic species, whose 

 eggs are generally deposited on the ova and larvae, or less 

 frequently on the pupae, or imagines, of the injurious kinds, 

 that thus become the hosts, on which the maggots prey when 

 they issue from the ovum. By the careful observer these 

 species will usually be found to exist in woodlands in much 

 larger number and variety than might be imagined. Hence 

 when anything like abnormal increase of the noxious kinds 

 takes place, so also do these, their natural enemies, multiply 

 in consequence of the greater amount of available nourishment 

 and the more frequent opportunities of reproduction thus 

 offered to them. 



i. The Predatory Species include, among the Coleoptera, the 

 sand-beetles (Cicindetidae), the predaceous land-beetles (Cara- 

 bidae) a large family among which many species of Carabus 

 and the tree-climbing Calosoma sycophanta and C. inquisitor 

 are particularly useful in killing the caterpillars of the Pine, 

 Spruce, and Processionary moths the dung-beetles (Staphylin- 

 idae\ the carrion-beetles (Silphidae\ the hister-beetles (Hister- 

 idae\ the nitid or shining beetles (Nitidulidae\ the thread-beetles 

 ( Colydiidae), the soft beetles (Malacodermatd), the gold-beetles 

 (Cleridae) especially Clerus formicarius, which is so frequently 



