Night Crawlers
Known as great fishing bait, night crawlers are one of the most common earthworms. They are mostly found in the northern United States, including many states in New England. Night crawlers can grow a little more than a foot long. Their bodies have have visible sections and a thick band across the middle. These worms must remain in cool areas to survive.
Field Worms
Field worms resemble night crawlers, but they are smaller in length and diameter. These worms are known to wiggle a lot when held and their bodies may curl up. While all earthworms feature both male and female reproductive organs, field worms go to the surface after it rains to mate with others. The worms' bodies stretch, connect using slime and disconnect shortly after.
Red Worms
Red worms are known as the gardener's worm because of the way they travel through the ground. These worms live close to the surface of a lawn, so they are constantly digging and composting soil for use in plants and vegetable gardens. Web-sites like Gardenworms.com actually sell the worms by the thousands because they help lawns so much. The worms are also used for fishing bait because their fast movements attract fish.
Manure Worms
Manure worms are one of the most commonly farmed worms because of their active breeding habits. During the middle of the night, worm farmers collect thousands of worms and put them in empty coffee cans. The worms are then distributed and sold. The worms are very skinny and hard to hook for fishing bait. They are fast diggers and can stretch their bodies a long way when facing resistance.
Palouse
According to Livescience.com, the Palouse earthworm is the rarest and looks nothing like others. It measures more than 3 feet long on average. Instead of the dark brown coloring of the other species, the Palouse is a light skin-toned color. The worms are only found in small sections of Idaho and have a flowery scent to them.