redia

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A larva of certain trematodes that is produced within the sporocyst and that can give rise to additional rediae or to cercariae.

Century Dictionary and Cyclopedia

1. n. The second larval stage of some fluke-worms or Trematoda, as Distoma, intervening between the condition of the ciliated embryo and the more advanced form known as cercaria. A redia is a sporocyst, containing the germs of other rediæ, which eventually develop into cercariæ. The redia of Distoma is also known as king's yellow worm. See cercaria (with cut) and Distoma.

Wiktionary

1. n. the larva of some trematodes, some of which become cercariae

GNU Webster's 1913

1. n. (Zoöl.) A kind of larva, or nurse, which is prroduced within the sporocyst of certain trematodes by asexual generation. It in turn produces, in the same way, either another generation of rediæ, or else cercariæ within its own body. Called also proscolex, and nurse. See Illustration in Appendix.