Internal Anatomy

The major elements of the neuroendocrine system are the brain, the subesophageal ganglion, three thoracic ganglia, and six abdominal ganglia (with thick, paired connectives between the ventral ganglia). Paired neurohemal corpora cardiaca are connected to the brain and frontal ganglion by strong nervous connections; the closely associated single median corpus allatum produces and releases juvenile hormone III and is in close proximity to the neurohemal dorsal aorta. The digestive system contains the typical regions of fore-, mid-, and hindgut (though gastic caecae are lacking); the midgut-hindgut junction is characterized by the presence of numerous long, slender (excretory) Malpighian tubules.

The female reproductive system consists of paired ovaries, lateral oviducts, a median oviduct, spermatheca (for sperm storage), and genital chamber. Earwigs are unusual in that the female genital opening (gonopore) is just behind the seventh abdominal segment. The ovaries are primitively polytrophic; in some species the long ovarioles branch off the lateral oviduct, while in others, short ovarioles appear in series around the oviduct. The viviparous species are pseudoplacental, with egg maturation and embryonic development taking place in the greatly enlarged vitellarium. The male reproductive system is complex, with paired testes, paired vasa deferentia, paired or single vesicula seminalis (for sperm storage), and a paired or single common ejaculatory duct ending in the sclerotized virga (penislike structure). Anatomy of the male reproductive system has been used extensively in classification schemes of earwigs, as discussed shortly.

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