THE EARWIGS OF CEYLON. 63 



Earwigs feed chiefly upon animal or vegetable refuse, but also devour ripe 

 fruit, the petals of flowers, etc- They are nocturnal insects, and in daylight 

 take shelter under bark, under stones, in holes and crevices, etc. They can 

 be found almost everywhere, and are often attracted into the houses by light. 

 The flattened forms are said to live chiefly under bark, and Bracliylahis and 

 Opisthocosmia under dried leaves or in very ripe fruit. In Europe onlv 

 Labia minor, L., is known to make any use of its wings, but in the Oriental 

 Region crowds are often taken at light. 



Little is really known in detail of their habits and economy, and careful 

 observation would be of inestimable value. Of their development 

 and economy all that is known we owe to Mr. Green's paper quoted 

 above. 



The chief characters that are used to discriminate the various species and 

 genera of earwigs are as follow : — 



In the head it is important to notice the number of segments in the 

 antennae ; these are naturally fragile, and liable to be incomplete, and so it is 

 as well to note the number as soon as possible after capture before they are 

 broken ; even in the living insect they are frequently mutilated. In some 

 genera there are more than thirty segments, in other there may be as few as 

 nine. It is also important to notice the shape, especially of the first few 

 segments. In those species in which the antennae are dark with certain 

 segments white, no great reliance is to be put upon which actual segment is 

 thus coloured, as this is a very variable character. The head offers no other 

 characters of much note. 



It is useful to observe the shape of the pronotum, and whether it is 

 broader or narrower than the head. The presence of a small scutellum 

 at the base of the elytra is characteristic of Neolohophora, Pygidicrana 

 and Diplatys. 



The elytra are most characteristic wiien rudimentary, in which case the 

 shape differs very considerably ; this is a most important point in the genera 

 Neolohophora and AnisolaUs. The wings are of little use for distinctive 

 purposes. 



The small tubercles which are present on the second and third abdominal 

 segments are useful characters, but sometimes they are small and difficult to 

 distinguish. This is especially the case in Carcinophora, where they are pre- 

 sent, but barely distinguishable, and in Diplatys, where they are difficult to 

 observe as being covered by the wings in repose. 



The shape of the last abdominal segment and of the penultimate ventral 

 segment is also to be noted. The legs do not offer many points ; the form 

 of the second tarsal segment is important. This is simple and cylindrical 

 ill many genera, and heart-shaped or lobed in others. This is a note- 

 worthy character, and specimens should be set in such a manner as to make 

 I he tarsi easily accessible with the magnifying glass. 



