606 provide space in which an embryo could grow and also prevent physical damage. Ander son (1972a) considered, however, that these functions are redundant and that the cavity must have an as yet unidentified function. Another possibility is that the amnion and its cavity are used to store wastes, which are thus kept separate from the yolk. The general method of amnion and serosa formation outlined above is found in all insect embryos (with some modification where immersion of the germ band into the yolk occurs) except those of Muscomorpha and Apocrita, in which, it will be recalled, the embryonic primordium covers most of the yolk surface. In these, embryonic membranes are greatly reduced or lost. In embryos of Apocrita the extra-embryonic ectoderm separates from the edge of the primordium and grows ventrally to form the serosa; that is, amniotic folds are not formed. In embryos of Muscomorpha neither an amnion nor a serosa forms, and the extra-embryonic ectoderm covers the yolk until definitive dorsal closure occurs (see below).

After the embryonic membranes form, the serosa in most insect eggs secretes a cuticle that is often as thick as the chorion. For several species, production of the serosal cuticle is closely synchronized with a peak of molting hormone in the egg (see Section 9).

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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