Page:The New International Encyclopædia 1st ed. v. 02.djvu/790

BEETLE. or below ground. Still another vast host, Ci- cindelidae, Carabid^, Dytiscidae, and Coccinellids, live on animal food, which cither the adults or their predaeeous larva? captuie alive, or appro- priate when found dead, according to the cus- tom of the species. In this fondness for decay- ing and exerementitious matter, often minute in quantity, they perform an excellent service.

ExE-MiES AND DEFENSES. Birds, rodents, frogs, toads, and reptiles all prey upon beetles, both adult and larval. Flies, wasps, mites, and pre- daeeous beetles feed on them, or lay eggs within them which develop at the expense of the strength and substance of their host. They are infested with parasitic worms and protozoa, fungi destroy them, and inclement weather and lack of food help to reduce their ranks. Against these adversities various beetles are more or less protected by having a coloration like that of soil, leaves, or the bark of trees, while certain others look like excrescences on the leaves of their food-plants, or caterpillar-dung, and still others hide themselves under heaps of their own frass. A few look like sticks and seeds, the cocoons of one form resembling the seed-pod of the food-plant. A good many feign death by dropping to the ground. The bombardiers (q.v.) shoot at a pursuer. The abdomen of a number of beetles is held up in a warning attitude, as if to sting. Certain longicorns have the disagree- able taste and smell of fireflies, and even possess yellow markings in the region occupied by their luminous disks. For the huninescenee character- istic of the Lampyrida?, etc., see Fireflies and LUMINCSITY OF AnIMAL.S.

Economic Import. The Blister-beetles (q.v.) are used to make blister-plasters, particularly the one commonly known as Spanish-fly. The grubs of various beetles are roasted and eaten by both white men and natives of the tropics; and the Romans, according to Pliny, fat- tened certain grubs (Cossus) with iiour, to pre- pare them for the table. This 'Cossus' was prob- ably a member of the genus Prionus, the larv« of which are still eaten in some parts of the world. The hard parts of brilliant tropical spe- cies are often mounted as jewels to form pins, cuflF-buttons, hat-pins, belt-buckles, and the like. Fireflies sewed iu gauze are used by Cuban

LARVA (GRUB) OF A BEETLE. The Ipjrs spring from the three thoracic segments; the remainder of the body consists of abdominal segments.

women to adorn ball dresses. Many beetles, such as those of the ladybird family, prey on plant-eating insects ; others, .such as carrion and dung, and the burying beetles, place theirs upon table refuse, and a great many beetles fertilize flowers. Taken as a whole, however, beetles are economically injurious; for they ravage growing and stored crops, living wood, lumber, both sawed and manufactured, carpets, furs, hides, woolen goods, cured meats, books, and zoological col- lections. The Dermestids (q.v.) are especially pestiferous.

Life-History. Owing to the difficulty of rear- ing beetle larvae, we know comparatively little of the life-history -of beetles. All undergo com- plete metamorphosis. The eggs are laid in the situations where the economy of the species de-

HEAD op A BEETLE LARVA. A, Labrum : b. Labial palpus; c. c, Maxillfe; tf, Max !ary palpi; f, f, Autenute; g, Mandibles.

mands that the grub should be born, in order to maintain itself — that is, upon or within ac- cess of its food. Thus aquatic beetles lay their eggs in the water, leaf-eaters upon plants, wood- borers beneath the bark and in crevices of tim- ber; the weevils upon tender seed-pods or young seeds, and .so on. The scarabs (see DrxG-BEETLE and Sc.rab) roll up their eggs in a ball of diy dung, and the burj'ing beetles place theirs upon the carrion which is buried to await the hatch- ing of the young, ^'hen the eggs are not laid so late as to be intended to remain dormant over winter, they hatch quickh', and the larva begins at once to feed upon its intended fare. The larvae are conuuonly called 'grubs,' are usually whitish or of dull, inconspicuous hues, and ordinarily have three pairs of legs, one pair for each of the first three thoracic segments, which may vanish in older stages ; but grubs that live within their food may be legless. Grubs may possess traces of still other legs, a number of them having a pseudopod on the posterior end of the abdomen. Like adult beetles, grubs have mandibulate mouth-parts, and certain forms liave channels in the mandibles thi-ough which liquid food is sucked. The larval state lasts for a number of years, which makes those species injurious to agriculture far more formidable than they might otherwise become.

Some beetles pupate in cocoons or cases, made of agglutinated bits of earth and wood. Those larva' that bore in wood go into the pupa stage in their burrows. Some forms pupate in the ground, others on the surface of the ground; while still others, such as the ladybird, suspend themselves to objects above ground by the posterior ends of the body. Several pupate in the last larval skin. The pupal state of the majority of beetles lasts only two or three