One of the flies belonging to the family Calliphoridae. Most blowflies are scavengers. Their larvae live in decaying flesh or meat, although occasionally they may live in decaying or suppurating tissue. However, one species, the screw-worm fly, Callitroga hominivorax, attacks living tissue, laying its eggs in the nostrils or open wounds of its domestic animal or human host, giving rise to myiasis.