Mosquitoes are small, midge-like flies which compose the family Culicidae. Females of most species are ectoparasites, whose tube-like mouthparts (called a proboscis) pierce the hosts' skin to consume blood. The word "mosquito" (formed by mosca and diminutive ito) is Spanish for "little fly". Thousands of species feed on the blood of various kinds of hosts, mainly vertebrates, including mammals, birds, reptiles, amphibians, and even some kinds of fish.