Most of us are at least somewhat familiar with the small German cockroach which is easily the most common cockroach found in our homes. We also have larger cockroaches that are mostly found outside of our homes but which, in certain conditions, can find their way inside.

1. American Cockroach, Periplaneta americana

Our largest cockroach (up to 1-1/2 inch). Color of adult is chestnut brown with brownish-yellow margins around the edges of the thorax. Nymphs are shiny reddish-brown. Both sexes have long wings and can glide from high places. Also called “Palmetto bug” in the south and “sewer roach” since it is the most common cockroach infesting sewers.

Habits: Can enter and reproduce in buildings where it is usually found in basements or on lower levels. It likes warm, dark, damp areas such as near steam pipes, boiler rooms, or near floor drains. It is less common in homes, but frequently invades commercial buildings such as restaurants, grocery stores, and also sewers. In New England, usually survives winter only indoors, in sewer systems, or deep in landfills.

For a photo and more on American cockroaches, see American Cockroaches Occupy Lower Levels of Buildings.

2. Oriental Cockroach, Blatta orientalis

Large cockroach (male up to 1-1/4 inch) but not quite as long as the American cockroach. Color is shiny black to reddish-brown. Unique in that the adult female is virtually wingless just like the nymphs. The adult male has wings but they cover only the front half of his back and he can’t fly either. Sometimes referred to as a “waterbug.”

Habits: Found outside in dark, damp, undisturbed areas around foundations, rock walls, woodpiles, in mulch, and sometimes in sewers. Hides during day and comes out to feed at night on garbage, dog poop, pet food, rotting fruit, and decaying materials. In homes, found in dark damp places like crawlspaces, basements, garages, laundry rooms, or near leaky pipes, sinks, or floor drains. In cold regions, they survive the winter indoors, outdoors in protected areas where they are inactive, or as egg cases.

For a photo and more on oriental cockroaches, see Oriental Cockroaches Can Become Indoor Pests.

3. Wood Cockroach, Parcoblatta pennsylvanica

Medium-size cockroach (up to 1 inch). The male and female look quite different. The male is light brown to chestnut brown with long wings and flies readily; female is smaller, dark, and virtually wingless. The reddish-brown nymphs look similar to oriental or American cockroach nymphs.

Habits: Temporary and seasonal pest, mostly in homes near woods. Normally found outside where they feed on decaying organic matter. Around homes, can be found in gutters, potted plants, under wood siding, or in firewood. During their May-June mating season, males will fly long distances to find females. Males fly to lights. If a female gets inside, multiple males may find their way indoors attracted by her pheromones. Rarely survive long indoors.

For a photo and more on wood cockroaches, see Meet the Wood Cockroach.