( 317 ) 



The number of bristles, moreover, is much smaller in Ilemimerus than in Arixenia. 

 The common earwig, too, has bnt a small number ol' bristles at the molar margin of 

 the lacinia, and the latter is much slenderer than in Arixenia, but bears two apical 

 teeth as in that insect. 



The onter lobe of the maxilla, the galea, is almost identical in Forjieulu, 

 Hemimerus, and Arixenia. It is gently curved inwards, and its transverse section 

 is circular. The apex is pale, without bristles and but slightly chitinised, serving 

 doubtless a sensory purpose. 



The maxillary palp consists of five segments, as in the allied insects. The two 

 proximal segments are very short, and the third is a little longer and stouter than 

 the fourth. The fifth bears at the apex short and stumpy bristles which difter 

 from the ordinary bristles with which the palp is clothed. There is, moreover, 

 a minute accessory segment at the tip of the fifth, as is the case in the labial 

 palp also. This accessory segment, which gives the palpi their very characteristic 

 appearance, is found in the earwigs as well as Hemimerus, whereas the Locusts, 

 Blattids, Mantids, etc., have quite different palpi. 



The gap in which the maxilla is inserted nearly extends to the hind edge 

 of the head, being separated from the occipital foramen only l)y the narrow 

 submentum, which is joined rigidly at each side to the lateral part of the capntal 

 capsule (PI. XVII. fig. 1). The submentum {sm, PI. XVII. fig. 7) is the posterior 

 sclerite of the second pair of maxillae or the labium. The suture which separates 

 it from the main part of the labium is quite distinct. The second sclerite is 

 the mentum. It is broader than long and strongly rounded at the sides, and 

 its anterior margin is incurved at each side, so that the angles, which are strongly 

 rounded, project a little. The surface is nearly flat, being slightly impressed 

 from the sinus of the anterior margin backwards and somewhat convex at the 

 sides. Neither the mentum nor the submentum shows a distinct trace of a 

 mesal suture. The two apical segments of the labium are divided in the middle 

 line, and therefore can not only execute a downward movement, but can also 

 move horizontally, especially the two apical lobes, which open and shut like 

 the maxillae. The third segment, or the palporium ( = palpiger), which bears the 

 palpi, is separated by sutures from the mentum as well as the two apical lobes, 

 which form the ligula {li, PI. XVII. fig. T). The apex of the lignla is white 

 and without bristles, and recalls the pale apex of the galea of the maxilla. The 

 inner edges of the two lobes of the lignla bear some rigid bristles. The labial palp 

 {Ip, PI. XVII. fig. 7) is composed of three segments as in the allied insects, 

 bearing like the maxillary palp a minute apical accessory segment. 



On the upperside of the apical lobes of the labium there lies the hypopharynx 

 (or eudolabiumj. It consists of a broader central flap and two narrow lateral 

 flaps ; the hitter are strongly chitinised at their onter edges and jiartly cover 

 the central flaj) in a dorsal view (PI. XVII. fig. 9). The chitinised edges of 

 the lateral flaps extend backwards for a short distance and send out a side-branch 

 towards the maxillae. The hypopharynx is remarkably similar to that of 

 Ilemimerus, whereas it differs somewhat in shajie from that of Forficula. 



Thorax. 



The prothorax is the longest of the three thoracic rings. The pronotum is 

 broader than it is long, and its lateral and posterior edges almost form an evenly 

 curved semicircle, reminding one of certain Fc.rliculids, The disc is feeblv convex 



