Beetles
(Coleoptera). Beetles form one of the most extensive orders of insects, there being upwards of 3000 known British species. They vary much in appearance, but a Beetle is readily recognised by its front wings, or elytra; these form a tough horny sheath or case, which lies over the real wings, and protects them when the insect is not flying. Sometimes, the elytra are very short the mouth is fitted with jaws for cutting. The metamorphosis is complete, i.e., the larva or grub is very unlike either the quiescent pupa or the perfect insect. The period that elapses before Beetles arrive at their perfect state varies from a few weeks to two or three years, but is usually rather longer than in Butterflies or Bees. Various Beetles attack growing plants and roots. Thus, Otiorhynchus sulcatus and O. picipes attack Vines, Roses, and other plants, gnawing off the bark. Some species of Beetles attack Mushrooms, while others bore into the wood of old trees, or eat leaves (e.g. Turnip Fly), or burrow in the leaves, or form galls on roots (Cabbagegall Weevil). Of some kinds, the beetles are hurtful; of others, the larvae. Many kinds, however, are beneficial, such, for instance, as the common Ground Beetle (Carabus, Fig. 224), and the Devil's Coach Horse (Ocypusolens, Fig. 225). These live upon other insects and snails. One kind of Beetle--the Ladybird--is very beneficial in a garden, as it preys upon the aphides, or plant lice. For instructions in dealing with the noxious kinds, see Asparagus Beetle, Bean Beetle, Beet Carrion Beetle, Click Beetle, Cockchafer, Lily Beetle, Rosechafer, and Turnip Fly.
BEET or MANGOLD FLY (Anthomyia betae). The maggots of this fly do considerable damage by feeding on the pulp of the Beet or Mangold leaves. The eggs are small, white, and oval, and are laid in small patches beneath the leaves; the maggots are about 1/3in. long, legless, cylindrical, and yellowish-white. As it is of such recent appearance in this country, specifics for its eradication are by no means numerous; but, according to Miss Ormerod, "the best treatment appears to be to nip it in the bud, where such treatment is possible, by destroying the infested plants, but generally by all means of good cultivation, or by special applications of artificial manure, to ensure a hearty growth, which may run the plants on past the power of average attacks to weaken the leafage to a serious extent."