Eurasia. The common earwig was introduced into North America in 1907 from Europe, but tends to be more common in the southern and southwestern parts of the United States. The only native species of earwig found in the north of the United States is the spine-tailed earwig (Doru aculeatum), found as far north as Canada, where it hides in the leaf axils of emerging plants in southern Ontario wetlands. However, other families can be found in North America, including Forficulidae (Doru and Forficula being found there), Spongiphoridae, Anisolabididae, and Labiduridae. Few earwigs survive winter outdoors in cold climates. They can be found in tight crevices in woodland, fields and gardens. Out of about 1,800 species, about 25 occur in North America, 45 in Europe (including 7 in Great Britain), and 60 in Australia. Morphology Most earwigs are flattened (which allows them to fit inside tight crevices, such as under bark) with an elongated body generally long. The largest extant species is the Australian giant earwig (Titanolabis colossea) which is approximately long, while the possibly extinct Saint Helena earwig (Labidura herculeana) reached . Earwigs are characterized by the cerci, or the pair of forceps-like pincers on their abdomen; male earwigs generally have more curved pincers than females. These pincers are used to capture prey, defend themselves and fold their wings under the short tegmina. The antennae are thread-like with at least 10 segments. Males in the six families Karschiellidae, Pygidicranidae, Diplatyidae, Apachyidae, Anisolabisidae and Labiduridae have paired penises, while the males in the remaining groups have a single penis. Both penises are symmetrical in Pygidicranidae and Diplatyidae, but in Karschiellidae the left one is strongly reduced. Apachyidae, Anisolabisidae, and Labiduridae have an asymmetrical pair, with left and right one pointing on opposite directions when not in use. The females have just a single genital opening, so only one of the paired penises is ever used during copulation. The forewings are short oblong leathery plates used to cover the hindwings like the elytra of a beetle, rather than to fly. Most species have short and leather-like forewings with very thin hindwings, though species in the former suborders Arixeniina and Hemimerina (epizoic species, sometimes considered as ectoparasites) are wingless and blind with filiform segmented cerci (today these are both included merely as families in the suborder Neodermaptera). The hindwing is a very thin membrane that expands like a fan, radiating from one point