. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. proct Fig. 158.—Locusta. Successive steps in blastokinesis. Sagittal sections, {am) Amnion, {ch) Chorion, {dc) Provisional dorsal closure, {do) Secondary dorsal organ. {gut) Mid-gut. {proct) Proctodaeum. {ser) Serosa, {stom) Stomodaeum. degenerate, being replaced by the definitive epidermis. Middorsally the provisional dorsal membrane is fused with the amnion which now forms the second provisional dorsal cl
. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. proct Fig. 158.—Locusta. Successive steps in blastokinesis. Sagittal sections, {am) Amnion, {ch) Chorion, {dc) Provisional dorsal closure, {do) Secondary dorsal organ. {gut) Mid-gut. {proct) Proctodaeum. {ser) Serosa, {stom) Stomodaeum. degenerate, being replaced by the definitive epidermis. Middorsally the provisional dorsal membrane is fused with the amnion which now forms the second provisional dorsal closure of the embryo. The splanchnic mesoderm now grows dorsad and separates the first dorsal closure from the amnion. The former provisional dorsal closure then degenerates, leaving the inner layer of the splanchnic mesoderm as a temporary mid- gut cover until the definitive mid-gut epithelium is formed. Shortly before the beginning of blastokinesis the amnion and serosa become secondarily attached to each other at the cephalic end of the embryo and then rupture there (Figs. 157, 158). The fate of the embryonic envelopes resembles that already described for the dragonfly. Locusta migratoria shows a marked blastokinesis, the embryo turning along the posterior pole of the egg through an angle of 180 deg. (Fig. 158).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Johannsen, O. A. (Oskar Augustus), 1870-1961; Butt, Ferdinand Hinckley, 1899-. New York, London, McGraw-Hill Book Company, inc.
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