. The Cambridge natural history. Zoology. EARWIGS 21 I individuals. There are seven pairs of abdominal spiracles, which, however, are very minute, and can only be found by distending the body as shown in Fig. 103. The ventral chain consists of nine ganglia (the sub-oesophageal centre is not alluded to by Dnfovir); the three thoracic are equidistant and rather small; the hindmost of the six abdominal ganglia is considerably larger than any one of the other five. The ovaries of Zahidura riparia and Forficula auricularia are extremely different. In L. riparia there are on each side five tubes, ea
. The Cambridge natural history. Zoology. EARWIGS 21 I individuals. There are seven pairs of abdominal spiracles, which, however, are very minute, and can only be found by distending the body as shown in Fig. 103. The ventral chain consists of nine ganglia (the sub-oesophageal centre is not alluded to by Dnfovir); the three thoracic are equidistant and rather small; the hindmost of the six abdominal ganglia is considerably larger than any one of the other five. The ovaries of Zahidura riparia and Forficula auricularia are extremely different. In L. riparia there are on each side five tubes, each terminating separately in an obliquely directed lateral part of the oviduct. In F. auricularia there is but one tube on each side, but it is covered by three longitudinal series of very short sub-sessile, grape-like bodies, each of the two tubes being much dilated behind the point where these bodies cease. The testes in earwigs are peculiar and simple; they consist, on each side, of a pair of curvate tubular bodies, connected at their bases and prolonged outwards in the form of an elongate, slender vas de- ferens. The structures in the males of several species have been described at some length by Meinert,-' who finds that in some species a double ejaculatory duct exists. The young is similar to the adult in form; in the winged forms it is always easy to distinguish the adult by the full development of the wings, but in the wingless forms it can only be decided with certainty that a specimen is not adult by the softer and weaker condition of the integuments. Scarcely anything appears to be known as to the life - history, except a few observa- tions that have been made on the common earwig; Camerano found ^ that this Insect has certainly three ecdyses, and possibly at present chiefly one of nomenclature, we make use of the more usual mode of expression. ^ As on last page, and also op. cit. v. 1868, p. 278. * ^ Bull. Ent. Ital. xii. 1880, p. Fig. 111. — Ovaries of Lahi-
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