Color: Females are usually black, sometimes brownish, with 2 reddish triangular markings on her underside that are often joined so they look like an hourglass shape.
Habitat: Black widow spiders live in protected places such as woodpiles, under stones and decks, in hollow trees or stumps, rodent burrows, or even in low branches; dry places in barns, sheds, meter boxes, barrels.
Biology: Most black widow spiders overwinter as immatures, becoming adults in spring, dying in late July.
Damage: They sometimes damage cultivated plants. European earwigs may damage vegetables, flowers, fruits, and ornamental plantings. Spiderlings are poisonous only if eaten during first 18 days, but lose their poison. Adult venom is different, a neurotoxin. Female is not aggressive except after egg laying and when guarding her eggs.
Food: Insects. Black widow spiders hang upside down from irregular webs one foot in diameter. The female avoids light and tends to seek prey at night.
Size: House spiders (American house spiders, domestic spiders) have an adult female body length of about 3/16 to 5/16 in (5-8 mm), including abdomen. The adult male is smaller.
Color: House spiders have a yellowish brown carapace. Abdomen is dirty white with a few dark spots.
Habitat: Outside in protected places, around windows and under eaves with some light to attract prey; inside in garages, sheds, barns, warehouses, in corners and closets, under furniture.
Biology: Female lays 250 eggs in a brownish silky sac with a tough, papery cover, about 1/4 to 3/8 in in diameter.
Damage: Dust collects in their many webs, built in trial and error fashion..
Food: Insects, but spiders can go for weeks or months without eating.