Apterygote Hexapods

in the Symphypleona and Neelipleona, and the mouthparts are enclosed within a pouch 115

formed by the ventrolateral extension of the head capsule. The mouthparts are typically of the chewing type, though in many species they are rasping or suctorial. The 4-segmented antennae vary greatly in length and each segment may be subdivided into two (segments 1 and 2) or numerous (segments 3 and 4) subsegments. Immediately behind the antennae is a structure of varied form, the postantennal organ, which appears to have an olfactory function. Compound eyes never occur, but a varied number of ocelli (up to eight) are found on each side of the head. The thoracic segments are distinct in Arthropleona, but not in Symphypleona and Neelipleona; in all species the prothorax is small or vestigial. In the Symphypleona and Neelipleona the thorax is fused with the abdomen and individual segments are not easily distinguished except at the posterior end. The legs have no true tarsus but terminate in one or two claws that arise from the tibia. No more than six abdominal segments can be distinguished at any time (even during embryonic development). The first abdominal segment bears the collophore (ventral tube), which arises by fusion and differentiation of the embryonic appendages. The tube contains a pair of vesicles that can be extruded by hemolymph pressure. The tube appears to have several functions, though it was originally named because it was thought to be adhesive (Greek colle, glue). Other likely functions include gaseous exchange and, especially, salt-water balance. Most Collembola have a springing organ (furcula) on the fourth abdominal segment, held under tension beneath the body by a hooklike structure, the retinaculum, formed from the appendages of the third abdominal segment. When released from the retinaculum, the furcula is forced downward and backward by both muscular action and hemolymph pressure. As it strikes the substrate, the animal is thrown through the air, sometimes a significant distance (e.g., up to 30 cm in some sminthurids). Abdominal appendages may be greatly reduced in small subterranean forms. Cerci are absent in Collembola. Some species are ecomorphic, their form changing from instar to instar as a result of unusual environmental conditions, others are cyclomorphic (having seasonally different forms and habits, usually in summer and winter), and some show epitoky in which reproductive instars are morphologically different from non-reproductive (feeding instars) with which they alternate.

Noteworthy features of the internal structure of Collembola are the absence of Malpighian tubules and, in most species, tracheal system. However, a pair of spiracles between the head and thorax, leading to tracheae in the head, sometimes also the body, have been reported for a few Symphypleona. The nervous system is specialized and includes brain, subesophageal ganglion, and three ventral ganglia, the ganglia of the abdominal segments having fused with the metathoracic ganglion.

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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