Structure

chapter 7 Adult. The plecopteran head is prognathous and bears a pair of elongate, multian-

nulate antennae, well-developed compound eyes, three (rarely two) ocelli, and weak, often non-functional biting-type mouthparts. Usually all the mouthparts are present, but in members of a few families the mandibles are vestigial. The thorax is primitive. Its segments are free and the prothorax is large. Two pairs of membranous wings are nearly always present, though brachypterous and apterous species occur at high altitudes and latitudes. The hind wing typically has a large anal fan, but this is reduced in the more advanced families. The wing venation is generally primitive, but considerable variation is seen within the order. In members of primitive families a typical archedictyon is developed to a greater or lesser degree; in those of advanced groups the number of branches of the longitudinal veins and the number of crossveins are greatly reduced. The abdomen contains 10 complete segments, with the 11th represented by the epiproct, paraprocts, and long cerci. In Nemouridae, however, the latter are reduced to an unsegmented structure used in copulation.

The esophagus is very long, the gizzard rudimentary, and midgut and hindgut short. There are between 20 and 100 Malpighian tubules. In primitive families the central nervous system includes three thoracic and eight abdominal ganglia, but in advanced groups the sixth to eighth abdominal ganglia fuse. The tracheal system opens to the exterior via two thoracic and eight abdominal spiracles. In males the testes meet in the midline, but their products are carried by separate vasa deferentia to a pair of seminal vesicles. Usually there is a median ejaculatory duct, but in some species the vasa deferentia remain separate until they reach the median gonopore located behind the ninth abdominal segment. In females the panoistic ovarioles arise from a common duct that joins the oviducts of each side. A spermatheca is usually present.

Larva. In general form larvae resemble adults, except for the absence of wings and the presence, in most species, of several pairs of gills. Primitively there are five or six pairs of abdominal gills, but in members of more advanced groups these are reduced in number and secondary gill structures may appear on more anterior regions of the body (mentum, submentum, neck, thorax, and coxae) or may encircle the anus. In addition to gas exchange, the gills are important osmoregulators, equipped with chloride-uptake cells, as is also seen in larval Ephemeroptera. In many species the legs are fringed with hairs that assist swimming.

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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