Psorophora varipes (Coquillett), a species native to the Americas, is a model for colonizing in laboratories in need of a substitute for the yellow-fever mosquito, Aedes aegypti (L.). It mates readily in cages of all sizes; embryos remain viable in eggs for months both at room and refrigerator temperatures; caged adults and larvae are hardy; the adult thrives on rodent and primate blood; it is multivoltine; and it has a short life cycle. An account of bionomic details essential for securing and maintaining colonies of P. varipes is given.