Abstract
Keys, descriptions, and illustrations are presented for the identification of the larvae, pupae, and adults of the four species of black flies known from Iceland, viz. Prosimulium (Prosimulium) ursinum, Simulium (Psilozia) vittatum, S. (Eusimulium) aureum, and S. (E.) vernum. Maps depicting their distributions within that country, and brief biological notes are given.