CHAPTER XVIII 

 THE WINGS OF THE DERMAPTERA 



The winged members of this order have four wings. The first pair of 

 wings are leathery, very short, without veins, and when at rest meet in a 

 straight Hne on the back, resembling the elytra of staphylinid beetles; the 

 second pair are large, with radiating veins, and when at rest are folded both 

 lengthwise and crosswise. The radiating veins extend from a point near 

 the middle of the length of the wing (Fig. 305). When the wing is not in 

 use that part over which these veins extend is folded in plaits like a fan, 

 after which the wing is folded twice crosswise. 



The part of the wing traversed by the radiating veins is the greatly 

 expanded anal area. The preanal area is much reduced and contains only 

 two longitudinal veins; this area is quite densely chitinized. 



Fig. 305. — Hind wing of an earwig. 



The tracheation of a hind wing of a nymph is represented by Figure 306. 

 There is a transverse basal trachea (Fig. 306, tb) connecting the costo-radial 

 and the cubito-anal tracheae. The tracheae of the cubito-anal group all 

 coalesce at the base forming a single large trachea, from which, however, 

 the cubital trachea soon separates (Fig. 306, Ctt). The anal trachea is 

 twelve-branched. 



In the wing of the adult there are three distinct ar.al veins (Fig. 305). 

 The first anal vein is ten-branched ; eight branches fonn a group of radia- 

 ting veins, and the other two branches arise separately between this group 

 of radiating veins and the base of the wing. The trachea: in the wing of the 

 nymph (Fig. 306) corresponding to the ten branches of the first anal vein 



(295) 



