DE. F. LEUTHNER ON THE ODONTOLABINl. 



411 



and from the gradual modification of the male mandibles in the species 1, 2, 3, on 

 the one side, and in 0. gmciUs (a), 0. dalmani (b), and 0. celehensis (c) on the other. 

 In the former species the females are so similar in form that, although I have examined 

 hundreds of specimens, I am hardly able to determine them with certainty unless the 

 exact locality is recorded. In the females of 0. gracilis and 0. dalmani the prothorax 

 is almost trispinose, as in the males. The strongly developed pro- and mesosternal 

 processes and the shape of the mandibles render it probable that these species are 

 oflFshoots of 0. lellicosus. It will always remain uncertain whether they should be 

 regarded as constant local races of 0. bellicosus, or as distinct species. In the Chinese 

 dwarf form, 0. platymtiis (PI. LXXXVIII. figs. 9-12), the prothorax is similar in 

 form in both sexes. In the larger males of 0. siva a front angle is developed ; but in 

 the males of the other species the prothorax is always distinctly trispinose. 



If we compare the forms of the mandibles of the males with each other we obtain 

 the following results : — 



In 0. lilatynotus, 0. siva, 0. gracilis, 0. dalmani, and 0. celehensis, the two basal teeth 

 are persistent, even in the terminal forms. In 0. lellicosus (PI. LXXXVIII. fig. 2) 

 we find three basal teeth, but in the largest specimens the first projects more inwards, 

 and the others disappear, so that the terminal form leads towards a mesodont form. In 

 0. alces this development proceeds further, and a fourth form makes its appearance in 

 which all the basal and central teeth disappear, and only the apical teeth remain. 



priod. 



amph. 



1. 0. plut^notus ; I 



2. 0. siva \ 



3. 0. gracilis 



4. 0. dalmani 



5. 0. cehbensis 



6. 0. bellicosus 



7. 0. alces 



mesod. 



telodout. 



Number of spines. 

 ... 4-5 



y.... 2-3 

 .. 0-1-2 



This differentiation of the mandibles is correlated with the diminution of the spines 

 of the front tibise, which seems to confirm the above phylogenetic origin of the species 

 (comp. p. 391, § 7). 



In the smallest priodont forms of 0. alces (PI. LXXXIX. fig. 7) the front angles of 

 the prothorax disappear, and only the middle spine projects. The analogy of this form 

 leads me to regard 0. camelus (PI. XCVI. figs. 7, S) as nearest related to the present 

 group, although it is certainly an abnormal form. 



3p2 



