Gut and Derivatives

As noted earlier, the stomodeum and proctodeum arise at the anterior and posterior ends of the gastral groove, respectively. Both develop as hollow invaginated tubes, the stomodeum slightly earlier than the proctodeum, and as they differentiate into the subdivisions of the foregut and hindgut, respectively, various associated structures arise.

On the roof of the stomodeum, evaginations or thickenings give rise to the frontal ganglion, hypocerebral ganglion, intrinsic cells of the corpora cardiaca, and ingluvial ganglia. At its anterior end, the proctodeum develops pouches, which are the rudiments of the Malpighian tubules. (In many insects additional tubules develop during larval life.)

The anterior and posterior midgut rudiments that appeared at gastrulation begin to proliferate at about the time of provisional dorsal closure to form the midgut. Each rudiment proliferates a pair of strands that grow caudad or cephalad, respectively, between the nerve cord and yolk. After strands from each rudiment meet in the middle of the embryo, they grow laterally and dorsally so as to eventually enclose the yolk mass. The cells then differentiate as midgut epithelium. Prior to this, in embryos of some species, the vitellophages form a temporary "yolk sac" around the yolk mass.

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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