The 'embryonic moults' of the milkweed bug as seen by the S.E.M.
Deposition, detachment and removal of the three embryonic cuticles are studied. The membrane-like cuticle 1 covers the embryo during katatrepsis and 'disappears' thereafter. Cuticle 2 deposition starts shortly before dorsal closure. Its apolysis is accompanied by contractions of the embryo. Ecdysis of cuticle 2 takes place during hatching. Only cuticle 3 (= first larval cuticle) shows differentiations like sensilla and cornea. Peaks of ecdysteroid (and probably JH) titre are observed during apolysis of cuticle 1 and cuticle 2 (Dorn, 1981). Transition from ectoderm to epidermis proper takes place shortly before and during onset of cuticle 2 synthesis.
D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology / Q000648:ultrastructure*; D006430:Hemiptera / Q000254:growth & development / Q000648:ultrastructure*; D007814:Larva / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning