. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. 406 EMBRYOLOGY OF INSECTS AND MYRIAPODS inents of the appendages. The third period may be divided into three parts: (1) the truly embryonic, until the first ecdysis and the rupture of the chorion; (2) the first fetal or first postembryonic stage, ending in the second ecdysis; and (3) the second fetal or transition stage, when the body elongates and possesses spontaneous movement. In the fourth, or adolescen
. Embryology of insects and myriapods; the developmental history of insects, centipedes, and millepedes from egg desposition [!] to hatching. Embryology -- Insects; Embryology -- Myriapoda. 406 EMBRYOLOGY OF INSECTS AND MYRIAPODS inents of the appendages. The third period may be divided into three parts: (1) the truly embryonic, until the first ecdysis and the rupture of the chorion; (2) the first fetal or first postembryonic stage, ending in the second ecdysis; and (3) the second fetal or transition stage, when the body elongates and possesses spontaneous movement. In the fourth, or adolescent, period there are several molts, ending with the maturing of the sex organs. In essential features the structure and development of the heart of LithoUus forficatus as described by Biegel (1922) resemble that of Scolopendra. The aorta, however, is ^^â ^^ ^'"â â â \ not differentiated, and the aortic / ,...-^.^ .'---v, \ arches are lacking. In place of them / iJ^^Alf^) \ 1 a large head blood sinus functions. Lateral transverse vessels likewise are replaced by a segmentally arranged system of blood lacunae. Above the heart is a small dorsal heart sinus. Instead of the asymmetrically ending genital duct, in Lithobius forficatus both right and left ducts are functional. DIPLOPODA, THE MILLEPEDES. Fig. 362.âPlatyrhacus amauros. Platyrhacus amauros Attems This species is found in the decay- Germ disk before Aexure (a) Anus . ^^^ ^^ ^^^ ^^^^ j^^ ^^^ ^^^^^ {ant) Antenna, {ma) Mandible, {mx) o ⢠i /. i ⢠Maxilla, {prz) Proliferation zone, plants On the island of AmboiUa {From Pflugfelder.) (Moluccas). The cggs, which are laid in loose clumps of 60 to 80 in mulch, measure about 1 mm. in diameter, are rich in yolk, and hatch in about 19 days. According to Pflugfelder (1932), the cleavage nuclei surrounded by a thin layer of cytoplasm and more or less connected with each other by cytoplasmic strands migrate to the periphery where they undergo further division to form a bl
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