186 THE PROTECTION OF WOODLANDS. 



grubs and mole - crickets ; shrew, hedgehog, weasel, pole - cat, stoat, 

 badger, and fox devour beetles and pupa?. 



2. Birds. The most generally useful are the cuckoo (the only bird 

 devouring hairy caterpillars), the starling, flycatchers, titmice, tree- 

 creepers, swallows, owls, and most song-birds ; then thrushes, blackbirds, 

 rooks, gulls, plovers, the kestrel, buzzards, woodpeckers, sparrows and 

 finches, crows, ravens, jackdaws and larks, which are of less use. 



3. Insects. Predaceous and parasitic insects on the whole do far more 

 than either mammals or birds to keep injurious kinds in check. The 

 predaceous kinds prey, often both as larva and imago, on the eggs, larvse, 

 pupae, and adults of noxious insects ; while the parasitic kinds generally 

 lay their eggs on the eggs and in larvse (less frequently in the pupa) or 

 adults) of the injurious kinds, on which the maggots feed when they 

 hatch out. The useful insects generally exist in woodlands in large 

 numbers ; and when noxious kinds increase abnormally, so also do the 

 useful kinds that feed on them. The useful insects belong chiefly to the 

 orders Coleoptera and Hymenoptera ; then to the Diptera, Ncuroptera. 

 Hemiptera, and Orthoptera; while the Lepidoptera contains no useful 

 genus, just as the Neuroptera contains no injurious genus, so far as 

 concerns the forester. 



(1) Predaceous Insects. Among Coleoptera, predaceous kinds include 

 tiger- or sand-beetles (Cicindclidce), predaceous ground-beetles (Carabidcv), 

 dung-beetles (Staphylinidce], carrion -beetles (Silphidce), nitid or shining- 

 beetles (Nitidulidce), thread-beetles (Colydiidce), soft-beetles (Malacoder- 

 mata, including gold-beetles, Cleridce), and lady -birds (Coccinellidw). 

 Clerus formicarius and Rhizophagns dcpressus are two very useful beetles 

 in Conifer woods, as they prey on the Pine-beetle. Clerus formicarius is 

 easily recognisable by its large black head, black antenna) with red-brown 

 tips, red-and-black thorax, and abdomen red at base and black behind, 

 with two well-marked transverse white bands across the wing-cases. The 

 dark-headed larva is rose-red, and consists of twelve segments, the first 

 three of which have legs. The first segment has a horny plate above, and 

 the second and third have each two small horny spots ; the last joint is 

 covered with a horny shield, and ends in two small knobs. Both beetle 

 and larva feed on larvae, pupse, and adults of destructive tree-beetles ; 

 and the larva) bore into the bark to hunt for prey. The beetle always 

 seizes its prey behind the head. It is also the most useful of insects in 

 keeping down bark-beetles (Scolytidce). Rhizophayus depressus is only 

 about | of an inch long, bright rusty red, with finely-punctured lines on 

 the wing-cases. The larva is about | of an inch long ; the head and 

 prothorax are reddish, and all the other segments whitish above and 

 reddish below. The last segment of the body is red-brown, with two 

 knobs above and a small motor-appendage below. Both beetle and larva 



