DK. F. LEUTHN'EE ON THE ODONTOLABUS'I. 397 



mandibles. Olivier considered it to be the female of his L. cdces, and gave a recog- 

 nizable figure of it (tome vii. pi. ii. fig. 3 h). He remarks, " La femelle ne diflere du 

 male qu'en ce qu'elle est plus petite, que les mandibules sont a peine de la longueur 

 de la tc'te, et qu'elles ont trois dentelures a leur base, et cinq a leur extremite." If he 

 had only examined the sexual organs, even in dried specimens, he would not have 

 fallen into this error, which was pointed out by Hope in 1845'. But Hope, in 

 avoiding Scylla, fell into Charybdis, and described the insect as a distinct species 

 under the name of Lucanus cumingi, Hope. 



(4) The fourth form^ with small scissor-shaped mandibles (PI. LXXXIX. figs. 6, 7), 

 has not yet been described. It appears to be quite a diff"erent species from any of 

 the preceding, as the mandibles are here replaced by isodontine scissors, as they may 

 be termed. This modification can be followed step by step, and will be discussed in 

 the next section. In passing from the third to the fourth form, the size gradually 

 diminishes, and the smallest specimens of the latter only measure 45 millim. in length, 

 which is 13 millim. less than the length of the largest females. 



I will now attempt to demonstrate the specific identity of the four different forms 

 already mentioned, and to show that 0. dux, Westw., 0. alces, Fabr., and 0. cumingi, 

 Hope, are not to be considered as independent species, but are only difi'erent forms of 

 one and the same species. 



This is shown by the gradual transition from form 1 to form 4, the last of which 

 resembles the female. 



(b) Modijication of the Mandibles in the Male. 

 The males of this species are less constant in form than the females. It is true that 

 the latter, like the former, vary in size, but the different parts of the body are always 

 uniformly developed in proportion, as is shown by the measurements of the comparative 

 proportions of seven different specimens selected at random. The tip of the scutellum, 

 between the elytra, is about the central point of the body of the female, as the tips of 

 the mandibles and of the elytra are equidistant from it'^. This is true both of the 

 largest and the smallest of the 111 specimens examined. 



' Hope, Catalogue of the Lucanoid Coleoptera, p. 17. 



° Oue or more of these four forms of mandibles reappear iu the males of every species ; and for convenience 

 of reference I designate them as follows : — 

 i. Forma telodonta. 

 ii. Forma mesodonta. 

 iii. Forma amphiodonta. 

 iy. Forma priodonta. 



(C/. also p. 433.) 

 ' This applies only to 0. alces. 



