. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. HYMENOPTERA 325 this dorsal strip become aggregated in the cephalodorsal region of the egg to form a more or less discoidal mass, the "cephalodorsal ; This body appears to be nothing more than a thickened anterior end of the dorsal strip. It later degenerates in the yolk, do. neurg Fig. 281.—Apis. Cross sections of successive stages, (do) Primary dorsal organ. iect) Ectoderm, {it) Inner layer
. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. HYMENOPTERA 325 this dorsal strip become aggregated in the cephalodorsal region of the egg to form a more or less discoidal mass, the "cephalodorsal ; This body appears to be nothing more than a thickened anterior end of the dorsal strip. It later degenerates in the yolk, do. neurg Fig. 281.—Apis. Cross sections of successive stages, (do) Primary dorsal organ. iect) Ectoderm, {it) Inner layer, {mge) Mid-gut epithelium, {neurg) Neural groove. iser) Serosa. {In part from Snodgrass.) Ectodermal tissue is formed from the lateral plates, mesoderm from the middle plate, and the mid-gut rudiments are interpreted by some writers as the entoderm. During the formation of the germ layers both the middle and the lateral plates show distinct evidence of body seg- mentation which appears to correspond to the definitive segmentation of the embryo. The serosa is single-layered and is formed from the dorsal half of the blastoderm. It separates from the dorsal margins (Fig. 281 A,ser) of the lateral plates and gradually grows over the ventral face (Fig. 281 B,ser).. 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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