Rolledwinged Stonefly

Earwigs: Order Dermaptera

Identification: Small to medium-sized, elongate, flattened. 4 wings (rarely wingless): FW (elytra) thickened, leathery, short, meeting in a straight line down back; HW membranous, at rest folded beneath FW. Cerci well developed and forcepslike. Antennae threadlike, about half as long as body or less. Tarsi 3-seg-mented. Mouth parts chewing. Metamorphosis simple. Similar orders: (1) Coleoptera (p. 146) with short elytra: no forcepslike cerci. (2) Orthoptera (p. 76): cockroaches have short feelerlike cerci and 5-segmented tarsi; walkingsticks in the western genus Timema (which have 3-segmented tarsi) have antennae more than half as long as body.

Immature stages: Similar to adult but wings small or absent. Habits: Earwigs are nocturnal, spending the day in debris, under bark, and in other protected situations; they are chiefly plant feeders or scavengers. Some species when disturbed eject a foul-smelling liquid from glands near base of the abdomen; this serves as a means of protection. Eggs are laid in burrows in the ground or in debris, and the female usually guards the eggs until they hatch. Cerci usually differ in shape in the sexes, being straight, stout, and closely approximated in the female, and more slender, curved, and pincerlike in the male.

Importance: The name '''earwig" comes from an old superstition that these insects get into people's ears; this belief is without foundation. A few earwigs occasionally are pests in buildings and some may damage cultivated plants. The pincerlike cerci are used in defense, and can sometimes inflict a painful pinch. Classification: Four families in N. America, separated chiefly by form of tarsi and antennae. No. of species: World, 1100; N. America, 18.

COMMON EARWIGS Family Forficulidae Identification: Brownish. 2nd tarsal segment lobed beneath, expanded laterally, and prolonged distally beneath 3rd segment. Antennae 12- to 15-segmented. Widely distributed.

The most common species in this family is the European Earwig, ForfĂ­cula auricularia Linn., 10-15 mm. It sometimes damages cultivated plants.

BLACK EARWIGS Family Chelisochidae Not illus.

Identification: Similar to Forficulidae but black, and 2nd tarsal segment not expanded laterally.

Our only representative of this family is Chelisoches morio (Fabricius), a large earwig occurring in California.

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