Embryonic Membranes, Yolk Cells, and Morphogenesis of the Stonefly Pteronarcys Proteus Newman1, 2 (Plecoptera: Pteronarcidae)

In an earlier paper (Miller, 1939) on the embryology of the stonefly Pteronarcys proteus Newman, the author described the egg, oogenesis, oviposition, and incubation, provided a synoptic table of the entire embryonic development, and dealt in detail with the early stages up to the formation of the embryonic rudiment (ventral plate or germ disc). The present paper continues the account with a description of the embryonic membranes, the yolk cells, changes in the yolk, and details of embryonic morphogenesis. Included under the latter head is an account of the pleuropodia.