Springtails are a very small insect resembling a flea, less than 1/10th inch in length. They can be found in very large numbers at times, usually in forest debris where there can be as many as 50,000 per cubic foot. While they can infest buildings, they are usually found under rocks (sometimes being called "rock lice"), compost piles, and around swimming pools. They will occasionally even be found in snow (where they are called "snow fleas"). They feed on algae and decaying plant matter, trying to stay in a moist environment. If they infest a house, they will be found in bathrooms, kitchens, and damp basements. They actually do little or no damage to their environment.
Eggs are widely scattered in soil, litter, sand, etc. They hatch in the late spring, and nymphs just look like tiny adults, maturing by late fall or early winter.