. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. 312 EMBRYOLOGY OF INSECTS AND MYRIAPODS Leiby and Hill (1923) state that this species develops both monembry- onically and polyembryonically. Both fertilized and unfertilized eggs will develop, the fertihzed eggs pre- sumably giving rise to females. The egg is somewhat larger than a single blastoderm cell of the host egg (Fig. 259). If the egg is inseminated, the sperm can be seen in a curved or arched posi
. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. 312 EMBRYOLOGY OF INSECTS AND MYRIAPODS Leiby and Hill (1923) state that this species develops both monembry- onically and polyembryonically. Both fertilized and unfertilized eggs will develop, the fertihzed eggs pre- sumably giving rise to females. The egg is somewhat larger than a single blastoderm cell of the host egg (Fig. 259). If the egg is inseminated, the sperm can be seen in a curved or arched position (Fig. 260A). Never more than one sperm is found in one egg. The so-called "germ-cell deter- minant" (oosome) is apparently lacking. The nucleus is regularly found near the center of the newly deposited egg. Later it increases in size and gives off two polar bodies. After the second division the second polar body is seen at the anterior end, near the first polar body. The oocyte nucleus (later the female pronucleus) after the ninth hour may be found in the posterior half of the egg, increasing in size. After the second maturation the male pronucleus becomes spherical and about the six- Fig. 259.—Platygaster. Egg of para- site (e) under the blastoderm {bid) of the host 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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