Argues that the semiperipheral development of Puerto Rico since around 1975 has created a relative labor surplus in formal sectors of the economy while increasing demand for cheap labor in the informal service sector. Describes migration of Puerto Ricans to and from the U.S. and of Dominicans to Puerto Rico. (AF)

Data from St. Barthelemy (French West Indies) show that, for people born from 1878 to 1967, neither cohort size nor fluctuations in external demands for labor had a lasting effect on the probability of eventual migration. Emigration slowed only after development of local tourism brought prosperity to the island. (AF)