210 Mr. Stephens's Description 



but in Chiasognathus they acquire an elongation exceeding that 

 of the body ; they are extremely strong and robust at the base, and 

 evidently capable of biting very sharply ; towards the middle they 

 become flattened, and at the tips they are incurved so as to cross 

 over each other — whence the origin of the name I have applied 

 to the genus* — the internal edge is irregularly serrated throughout, 

 with a large tooth towards the base, and the apex has an acute 

 recurved hook (Plate X. Fig. 4). In the genus Lucanus a small 

 tubercle may be observed at the outer base of each mandible ; 

 in the insect now under examination this is greatly developed, 

 and forms an acute spinous process about one-third the length 

 of the mandibles, serrated within, and pointing inwards, so that 

 in situ the two cross each other towards the apex similarly to the 

 mandibles themselves. 



The upper lip (labrum,) is very distinct, being composed of 

 a coriaceous plate with a strong rib down the centre. 



The lower jaws (maxillce, Plate IX. Fig. 4.) are small, but the 

 apical portion is very long and delicate, and fringed with very 

 slender hairs: — the maxillary palpi are elongate, slender, with the 

 basal joint very short, the second nearly as long as the others 

 united, sub-clavate, the third half the length of the second, the 

 terminal elongate, somewhat attenuated. 



The lower lip [labium, PI. IX. Fig. 8.) is membranaceous, with 

 two, rather broad, flat, elongate, lacinia?, the extreme edge of which 

 is tinely ciliated : — the labial palpi are short, with the basal joint 

 very short, the second rather longer, the terminal one nearly as 

 long as the other two united, and attenuated. 



* Xmfw deciisso, Tva0w; maxilla. 



