408 DR. F. LEUTHNEE ON THE ODONTOLABINI. 



I. Neolucanus. 



Following Parry's example, I have endeavoured to divide the species of each genus 

 into small sections, according to their actual affinities, both on practical and theoretical 

 grounds ; but I have slightly modified Parry's arrangement by commencing with species 

 in which the males most resemble the females and ending with those in which the 

 sexes are most dissimilar (comp. the preceding diagram, p. 407). 



The first section contains small species presenting very slight sexual differences, as 

 is the case with A'. laticoUis (PL LXXXIV. fig. 1 d , fig. 3 ? ), and I therefore leave 

 them unnoticed. The sexual differences are equally slight, both in the mandibles, the 

 canthus of the eyes, the shape of the head and prothorax, and in the comparative 

 length of the front tibiae. 



Nothing can be said of the sexual differences of N. lanshergii, N. muntjac, and N. 

 cingulatus, as only one sex of each is known. The geographical distribution and great 

 similarity of these species render it probable that they are all very closely allied. 



The second group may be more profitably studied. In the North-Indian N. casta- 

 nopterus the mandibles are priodont in all the specimens examined by Parry, Bates, 

 and myself; and the male (PI. LXXXIY. fig. 13) and female (fig. 14) exhibit very 

 slight differences in the head and canthus. But the mf)st nearly allied species, N. 

 swinhoii (PI. LXXXIV. figs. 15, 15 5 d , 10 ? ), from Formosa, is not only larger, but 

 further differentiated ; as in all the largest telodout forms, the mandibles are forked at 

 the tip. But the smaller specimens (fig. 15 J) retain the priodont form of their 

 progenitors. In the female the slight difference from the male mandibles necessitates 

 the remarkable widening of the canthus (for defensive purposes'?) which gives the 

 head such a peculiar triangular form. The slight variations in the shape of the 

 prothorax and elytra are unimportant. The coloration of the whole insect and a slight 

 but important morjjhological character — the hairiness of the mentum in the males — are 

 quite constant. In N. castanopfems the chestnut-brown elytra are marked with a 

 black transverse basal band (figs. 13, 14), which is nearly obsolete in N. swinhoii. 

 The allied species K pallescens (PI. LXXXV. fig. 2) and N. imrriji (PI. LXXXV. 

 fig. 4) illustrate this. In the former the elytra are dark brown, with only a trace of a 

 narrow pale border, which runs from the tip to the middle, where it ceases. In the 

 allied JV^. parryi there is a triangular mark in the middle of each elytron in both sexes. 

 This coloration is repeated, somewhat modified, in the female of N. maryinatus 

 (PI. LXXXV. fig. 3), whereas the supposed male (fig. 1) is dark chestnut-brown. 

 The differences of these species are very slight, apart from their constant local colour- 

 variations. The hairy mentum in the males of these species is so characteristic that I 

 rightly concluded, before the discovery of the male of iV. iHirryi, that it would also 

 exhibit it. If fig. 1 is really the male of ]^. marginatus (which its analogy with 

 Odontolabis stevensi renders probable), the gap between this species and N. lama (fig. 14) 



