Title: The Internal Thoracic Skeleton of the Dragonflies (Odonata; Suborder Anisoptera)
Abstract: The dragonfly thorax has evolved from the generalized and primitive type of insect thorax along peculiarly specialized lines. The large flight muscles are associated with a mesothorax and a metathorax which are greatly enlarged and skewed so that the epimera and episterna slope backwards from the coxae towards the wing bases. (Needham and Anthony, 1903). This skewness has gone so far that the apparent top of the thorax is formed, not by the scutum, but by the side pieces, the episterna. As a result of the rearward crowding of the wings, these sclerites have expanded upwards and united along the mid-dorsal line in a carina that extends between the prothorax and the mesothoracic scutum. (Plate II, fig. 1). Similarly, much of the ventral side of the dragonfly thorax is formed, not of the sternum, but of the metathoracic epimera, which have expanded downwards and fused along the mid-ventral line, due to this same skewing process. Thus, in the dragonflies, the thorax is so constructed that the legs are crowded forward, close to the head, While the wings are pushed backwards. The first pair of wings usually lies above or behind the third pair of legs.
Publication Year: 1937
Publication Date: 1937-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 6
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