Two new phoretomorphic Siteroptes from galleries of the southern pine beetle
This paper provides taxonomic descriptions of two pyemotid mite species displaying polymorphic features discovered by Moser & Cross(1975). Polymorphism in the Acarina was first noted by Canestrini in 1888 for Rhizoglyphus echinopus (Fumouze & Robin). He associated the heteromorphic male with the normal homeomorphicm ale of this species. Later, Michael(1901) substantiated Canestrini's discovery and introduced the term hypopus for another stage or form (deutonymph) of the same species. This discovery had great bilogical significance. It showed that mites made adaptations to environmental conditions by physiological changes and that this form or stage was not a separate taxon. Reports of observations and studies on polymorphism in the Acarina are few. Oudemans (1906) and Baker (1949) reported that heteromorphic males occurred in the family Cheyletidae. Recently, SMiley [in press] and smiley and Moser (1976) have studed a predatory male cheyletid mite which isn ow known to be exemplify such a condition. Previously, this characteristic has been reported only for the male. Recently, it was discovered in the family by Rack (1974), Cross & Moser (1975) for the family Pyemotidae.