INTEODTJCTIOX, 7 



common to find wings well developed or abbreviated in one and the 

 same species {Labia spp., &c,). In addition to the fan-like radiating 

 veins mentioned there is a curved transverse vein, the radial vein, 

 which runs the length of the wing and remains at a more or less 

 constant distance from tlie axillary or anal margin of the wing. 



The wings are exceedingly delicate, and their unfolding is a 

 matter of great difficulty. In fresh or highly relaxed specimens 

 they may be teased open with a line pair of forceps and a camel's- 

 hair brush ; a glass tube, drawn out to a capillary point, is useful 

 to blow them gently out ; but considerable practice is required 

 before they can be expanded without tearing. This operation, 

 however, is by no means necessary, as the wings are scarcely ever 

 referred to for distinctive characters, and there appears to be little 

 diversity in the venation. 



The legs offer very useful characters. The femora are generally 

 rather compressed, but they are decidedly thickened in Timomenvs. 

 They are strongly compressed in the Pygidicranicke and furnished 

 with little keels. The tihioi are gently curved as a rule and 

 compressed ; the upper margin at the extreme apex is flattened 

 and rather hollowed; in Ex>/pnus, Chelisoches and the allied 

 genera, this character takes the form of a well-marked furrow or 

 sulcus, which extends for one-third or one-half the length of the 

 tibia. The tarsi ha\e three segments : in Apachyus the first 

 segment is much shorter than the third, but as a rule the first 

 segment is longer than the other two united. The second 

 segment is invariably the shortest ; in Lahia it is very minute ; 

 the greatest length is attained in the Bracliylabina; ; as a rule it 

 is cylindrical, like the other segments (Labidurido', Labiidce, &c.), 

 but in the Chclisoclunm it is produced into a long narrow lobe 

 under the third segment; in the other Forjiculidce it is broadened 

 and dilated into a heart-shaped lobe. The third segment is 

 usually about half as long as the first, and generally cyhndrical ; 

 it is rather short and broad in the Chelisocldnai. The tarsi are 

 depressed. In Diplatys and some other genera there is a indvUlus 

 or pad between the claws of the tarsi, but this shrivels up so much 

 in drying that it it is not of great value as a character. The 

 third segment is armed with a pair of claws. The tarsi are 

 generally strongly pubescent and furnished with long stiff' bristles. 

 The legs are long and slender in the Opisthocosmiinai and in some 

 genera of the Chelisochina;, but as a rule they are relatively short. 

 The hinder pair are always longer than the middle, and the middle 

 than the anterior pair. 



The abdomen is the most prominent part of an earwig. It is 

 elongate, and in bulk equal to the whole of the rest of tlie insect. 

 In Solenosoma it is almost perfectly cylindrical ; in many Opisilio- 

 cosmiincB it is spindle-shaped, that is, thickest in the middle, but 

 convex, with an almost circular cross-section ; in Diplatys and 

 Pygidicrana it is also convex, but narrowest in the middle (in the 

 male); the commonest form of the abdomen is more or less 



