Flea is the common name for insects of the order Siphonaptera, which are wingless insects with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living thanks to the blood of mammals (including bats and humans) and birds. Fleas are a nuisance for you and your pets and can cause medical problems transporting bacteria that can lead to diseases. If you find any fleas in your home, contact Bugs Or Us before they spread.