Structure

The great structural diversity found in the Diptera reflects the variety of niches that the true flies have exploited.

Adult. Adults range in size from about 0.5 mm to several centimeters and they are generally soft-bodied. The head is relatively large and highly mobile. It carries well-developed compound eyes, which in males are frequently holoptic. The antennae are of varied size and structure and are important taxonomically. In Muscomorpha-Schizophora there is a n-shaped ptilinal (frontal) suture that runs transversely above the antennae and extends downward on each side of them. This suture indicates the position of the ptilinum, a membranous sac that is exserted and distended at eclosion in order to rupture the puparium and assist a fly in tunneling through soil, etc. The mouthparts are adapted for sucking and are described in Chapter 3 (see Section 3.2.2 and Figures 3.14-3.16). The prothoracic and metathoracic segments are narrow and fused intimately with the very large mesothorax, which bears the single pair of membranous wings. The hind wings are extremely modified, forming halteres, small, clublike structures important as organs ofbalance (see Chapter 14, Section 3.3.4). In a few species halteres and wings are reduced or absent. The legs almost always have five-segmented tarsi, and in some species one or more pairs are modified for grasping prey. Primitively, there are 11 abdominal segments, but in most Diptera this number is reduced and rarely more than 4 or 5 are readily visible. Frequently, the more posterior segments (postabdomen) are telescoped into the anterior part of the abdomen (preabdomen) (see Figure 3.29). The postabdomen thus formed is used as an extensible ovipositor. The male genitalia are complex and their homologies uncertain because of the rotation of the abdomen and asymmetric growth of the individual components during the pupal stage.

In most Diptera the cibarium is strongly muscular and serves as a pump for sucking up liquids into the gut. In the bloodsucking Tabanidae and Culicidae a large pharyngeal pump is also present. The alimentary canal is, in most primitive forms, relatively unconvoluted. In Muscomorpha, however, it is much more coiled because of the increase in length of the midgut. The esophagus divides posteriorly into the gizzard and, usually, one diverticulum, the food reservoir (misleadingly called the "crop"). In Culicidae three diverticula are found. In Nematocera the midgut is a short, saclike structure; in Muscomorpha it is long and convoluted. Generally there are four Malpighian tubules that arise in pairs from a common duct on either side of the gut. In the nervous system a complete range of specialization

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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