A new subspecies of the endemic Cuban swallowtail butterfly, Parides gundlachianus C. Felder & R. Felder, is described, P. g. alayoi n. subsp., from a western locality, in Pinar del Rio Province. Field observations on the behavior and habitats of these populations and in centers ofabundance of the typical insect in eastern Cuba are described. Variation in adult size is recognized as an altitudinal cline. Biogeographical aspectsof this and other Cuban papilionids are discussed, and the need for conservation and protection of the western populations is stressed.
