Dermaptera 



171 



membrane by a fan-like radial closing and two 

 transverse folds can be tucked away beneath the firm 

 basal piece, which is itself hidden under the forewing, 

 its tip only projecting. A very large number of 

 Earwigs, however, have the wings reduced to mere 

 vestiges or entirely absent. 



The tail-forceps are very characteristic organs of 

 Earwigs, such appendages being unknown in any 

 other insects save the lapygida^ (described above). 

 They are developed from the limbs of the eleventh 

 abdominal segment in the embryo, which, as usual, is 

 fused with the tenth in the adult. The forceps of 

 male earwigs are usually longer 

 and more complex than that of 

 the female. In some genera the 

 two limbs of the forceps are not 

 symmetrical, one partially over- 

 lapping the other. 



The most important character 

 of Earwigs is the nature of their 

 genital ducts, which are entirely 

 mesodermal in origin, and not 

 formed partially by an ectoder- 

 mal in-pushing, as in the 

 Orthoptera and almost all other 

 insects. In the genus Labidura the male ejaculatory 

 ducts are paired ; in Forficula these ducts are primi- 

 tively paired, but one disappears in the course of 

 growth, the other taking up, secondarily, a median 

 position (49). 



Development and Habits. — Earwigs undergo 

 no transformation in their growth, the young being 

 usually hatched in a state closely resembling that 

 of the adult. It has lately been shown, however, 

 that a Ceylonese earwig (106) is hatched with long 

 jointed cercopods, like those of Campodea, which 



Fig. 93. — Common Earwig 

 {Forficula auricularia, 

 Linn.) Europe. Magni- 

 fied. 



