DR. F. LEUTHNEE ON THE ODONTOLABINI. 409 



and N. saundersi (fig. 13), the largest species of Neolucanus, would be bridged over in 

 a very une.xpected manner. The females of the two latter species (figs. 9, 11, 12) are 

 so variable that it is not easy to separate them, though the males are more easily 

 distinguishable. In N. lama the mandibles are always priodont in small males, but they 

 are forked at the tip in larger ones. In K saundersi they are more developed. The 

 priodont form (fig. 16) much resembles that of N. lama 6 . In rather larger specimens 

 a gap appears in the middle, and an amphiodont form is thus developed. The basal 

 teeth, traces of which are visible on both sides in fig. 13 (Parry's type), are absent in an- 

 other specimen in the British Museum, only the apical teeth remaining. Oddly enough, 

 in large specimens an upright tooth is developed at the base of the mandibles ^, which 

 is indicated as a mere rudiment in the smaller priodont forms. 



N. championi (fig. 8 rf , fig. 6 $ ), N. sinicus (fig. 7 <? , fig. 5 ? ), and N. oberthilri 

 exhibit only unimportant differences in size and shape, and are chiefly distinguished by 

 their colour. 



The large species of Neolucanus lead us, without any very wide interval, to the first 

 section of the genus Odontolahis, Hope. 



II. Odontolahis. 



In this genus, 0. siva, Hope, and its allies exhibit the least divergences in the females. 

 Their resemblance to the last species of Neolucanus is very remarkable ; they are found 

 in the same localities, and are very easy to mistake for one another. But the similarity 

 of the small males (PI. LXXXVI. fig. 6, and PI. LXXXV. fig. 15) is not without 

 significance, as it has led experienced coleopterists to treat 0. siva and K lama as 

 one species ! The similarity in form and colour between certain parallel species of 

 Neolucanus and Odontolahis, which inhabit similar localities, is so great that we are 

 sometimes reminded of the well-known cases of true mimicry in Lepidoptera noticed 

 by Bates and Wallace. 



' The iuteUigent observer will ask why this genus should develope so remarkable a structure (so similar to 

 the genus Prismorjnaihus, Motsch.), which one would think would not be developed, owing to mechanical 

 obstacles. But we shall find the explanation in a direction where we should least have expected it. The 

 female mandibles are flattened, and the right mandible, when closed, partly overlaps the left. Their structure 

 allows them to expand very widely, and the concavity behind the inner teeth exactly corresponds to the 

 rounded epistoma-like clypeus (PI. LXXXIV. fig. 16, PI. LXXXV. fig. 9). At the point of the upper surface 

 where the right mandible overlaps the left, we frequently find a projection which prevents their further closing. 



The length and thickness of the male mandibles render it impossible for them to overlap, except at the tip, 

 and the pressure of the mandibles may have given rise to a projection which gradually developed into a large 

 tooth, which would be produced on the opposite side by the law of bilateral symmetry. The base of the 

 mandibles is exposed to similar friction, where the upper side touches the frontal margin (apart from the 

 probability of the mandibles being also used for protection when the animals are fighting). Rudiments of 

 these teeth are found in the males of N. swinhoii (PI. LXXXIV. fig. 15) and other species. 



VOL. XI. — PAKT XI. No. 4. — November, 1885. 3 p 



