Abstract
Ecdysone titer in developing and diapausing eggs of the silkworm, Bombyx mori, was estimated by biological assay using isolated abdomens of Sarcophaga. Quite high ecdysone titer was found in eggs 24 hours after oviposition. The level diminished during the diapause and was re-elevated upon resumption of embryonic development. An essential role for ecdysone in embryonic development is suggested.
