These chewing insects belong to the order Dermaptera. They undergo incomplete metamorphosis (hemimetabolic insects). Their life cycle includes three distinct stages: egg, larva and adult.
Eggs: Pearly white, smooth and ovoid.
Larvae: Similar to adults, only smaller (2 mm) and greyish.
Adults: Elongated and flattened, shiny, brownish-red bodies. They are about 2 cm long. They have two long antennae on the head and chewing mouthparts. They have six slender legs on the thorax and two pairs of small wings, which they rarely use. They have two pincer-like appendages (cerci) on the abdomen; males have large, curved cerci and females have small, nearly straight ones.
Earwigs reproduce sexually. Males and females mate primarily in July and August.
In fall, as soon as there is regular nighttime frost, adults burrow into the ground for the winter. Most males die over the winter, but females survive until June.
Between mid-November and mid-December, each female lays about 50 eggs in a burrow in the soil. She watches over the eggs until they hatch (in mid-May) and then cares for the young larvae for two or three weeks, until their first moult. In late May, the young leave the burrow at night in search of food, returning during the day. Soon they leave the burrow and seek out other dark sheltered spots in which to hide during the day.
The larvae progress through four moults before reaching the adult stage. In Quebec, the first adult earwigs usually appear in July and are active until October. There is a single generation each year.