The German cockroach (Blattella germanica) is a small species of cockroach, typically about 1.1 to 1.6 cm (0.43 to 0.63 in) long. In colour it varies from tan to almost black, and it has two dark, roughly parallel, streaks on the pronotum running anteroposteriorly from behind the head to the base of the wings. Although it can barely fly, although it may glide when disturbed. Of the few species of cockroach that are domestic pests, it probably is the most widely troublesome example. It is very closely related to the Asian cockroach, and to the casual observer, the two appear nearly identical and may be mistaken for each other. However, the Asian cockroach is attracted to light and can fly like a moth, while the German cockroach cannot.
The German cockroach occurs widely in human buildings, but is particularly associated with restaurants, food processing facilities, hotels, and institutional establishments such as nursing homes. In cold climates, they occur only near human dwellings, because they cannot survive severe cold. However, though they would soon die in the outdoors on their own, German cockroaches have been found as inquilines (“tenants”) of human buildings as far north as Alert, Nunavut. Similarly, they have been found as far south as southern Patagonia.