IMMATURE STAGES OF SCAPHISOMA-CASTANEUM MOTSCHULSKY (COLEOPTERA, STAPHYLINIDAE, SCAPHIDIINAE), WITH OBSERVATIONS ON NATURAL-HISTORY, FUNGALHOSTS AND DEVELOPMENT

Eggs, larvae, pupae and known aspects of the life history and habits o f Scaphisoma castaneum Motschulsky are described based upon field coll ected and laboratory reared material. Immatures were collected and rea red from the polypore fungus Auriporia aurea (Peck) Ryvarden found wit hin a downed log of Pinus ponderosa Douglas. Approximate duration of t he developmental stages at room temperature (22-24 degrees C) in days were: egg 4-6; larvae, instar I, 1-2; instar II, 2-4; instar III, 4-6; prepupa, 1-2; pupa, 9-12. Complete developmental time of S. castaneum ranged from 21-25 days (mean 22). Second and third larval instars wer e observed to construct longitudinal, meshwork-like canopies from dige sted food excreted from the anus over occupied parts of the host fungu s. Descriptive illustrations of the third larval instar and pupa are p rovided. Morphological and behavioral comparisons to S. impunctatum Re itter, the only other species of New World Scaphisoma with described i mmatures and habits, are made.