THE CLASSIFICATION OF INSECTS 61 



can live under water for many weeks it has at times caused 

 some trouble by getting into cisterns." At least one 

 species (Anurida maritimia) frequents salt water, being- 

 found abundantly upon the surface of rock pools on the 

 shores of the English Channel. Others are characteristic 

 of Alpine regions, where they disport themselves on the 

 surface of the snow or ice, and are known as " snow- 

 fleas " or " snow- worms." 



Order II. — Dermaptera. 



This is the order of the earwigs. These insects were 

 formerly placed with the Orthoptera, but owing to 

 certain peculiarities of structure they are now usually 

 treated as a distinct group. The fore-wings are 

 represented by oblong plates, which serve as covers for 

 the hind-wings. The latter are unique structures, con- 

 sisting of a firm basal piece, whence radiate numerous 

 nervures which support a delicate membrane. By a fan- 

 like radial closing, and two transverse folds, each hind- 

 wing can be packed away beneath the corresponding 

 fore- wing, or elytron. Another characteristic feature is the 

 pair of forceps at the end of the abdomen. These vary 

 very much in shape in different species, while they 

 are usually larger and more complex in the male than 

 in the female. Some species, at least, employ their for- 

 ceps in the process of packing up their wings. Earwigs 

 have biting mouth-parts, and feed chiefly upon vegetable 

 substances ; but they also attack and devour other insects. 

 Their metamorphosis is incomplete, the young resem- 

 bling their parents except in size and the absence of wings. 

 They are most abundant in the tropics, but they are 

 represented in all parts of the world. The common 

 British earwig is Forficida aurieularia, while a much 



