Description of the immature stages of Ixodes (Pholeoixodes) baergi (Acari: Ixodidae), a parasite of cliff swallows in the United States.

The larva and nymph of Ixodes (Pholeoixodes) baergi Cooley & Kohls are described for the first time. This tick has been collected only in the United States on cliff swallows, Hirundo pyrrhonota, in their nests, or in adjacent habitats. To date, it has been reported from Arkansas, Colorado, Illinois, Oklahoma, and Texas. Brief notes on the synchronization of the life cycle of I. baergi with that of its host are included.