Rotation of Embryo in Eggs of Petaluridae, Gomphidae, and Corduliidae, in Connection with Types of Oviposition, Egg Shape and Germ Band (Odonata, Anisoptera)

In gomphid Sieboldius albardae, Davidius nanus and corduliid Somatochlora viridiaenea atrovirens, the eggs are ellipsoidal like those of Libellulidae, and the embryos exclusively show a gravity-dependent rotation to take a venter-up position just after revolution quite similarly to libellulid embryos. The same is true for petalurid Tanypteryx pryeri, and their shape is ellipsoidal. Thus in the ellipsoidal eggs the gravity-dependent rotation takes place without reference to systematic positions. Aeshnid Aeshna juncea and Gynacantha japonica embryos never rotate during development like A. nigroflava embryo.