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82 expanded posterior area (the ano-jugal area or vannus), several fold lines may occur. The principal wing areas are the jugum, behind the jugal fold, and the clavus, the area between the claval furrow and jugal fold in wings without a vannus. The vannus extends between the clavus and the jugum and therefore includes any vannal fold lines. The remigium is the area anterior to the claval furrow.

Various other terms may be encountered in wing descriptions (Figure 3.27). Because the wing is approximately triangular, it has three margins: the anterior costal margin, lateral apical margin, and posterior anal margin. These margins form three angles: the humeral angle at the wing base, the apical angle between the costal and apical margins, and the anal angle (tornus) between the apical and anal margins. In Psocoptera, Hymenoptera, and Odonata an opaque or pigmented area, the pterostigma, is found near the costal margin of the wing. The areas between adjacent veins are referred to as cells, which may be open (when extending to the wing margin) or closed (when entirely surrounded by veins). The cells are named after the longitudinal vein that forms their anterior edge.

Wing Modifications. There are many modifications of the typical condition in which the insect has two pairs of triangle-shaped flapping wings. The modifications fall, however, into two broad categories: (1) Those that lead, directly or indirectly, to improved flight (see Wootton, 1992); and (2) those in which a wing takes on a function entirely unrelated to movement of the insect through the air. Both types of modification are possible in the same insect.

It seems that the two-winged condition is aerodynamically more efficient than the four-winged condition, and in a number of insect orders wing-coupling mechanisms have evolved that link together the fore and hind wings on the same side of the body (Tillyard, 1918). The precise nature of the coupling mechanism varies, but usually it consists of groups of hairs, the frenulum, on the anterior basal margin of the hind wing that interlocks with hairs or curved spines, the retinaculum, attached to various veins of the fore wing (Figure 3.28). The other way in which the two-winged condition has been achieved is through the loss, functionally speaking, of either the fore wings (in Coleoptera and male

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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