DR. F. LEUTHNER ON THE ODONTOLABINI. 389 
a single species (0. alces). Taking this as a starting-point, I studied the species which 
stand nearest to it morphologically, and thus gradually enlarged my horizon, until I 
was at length enabled to examine the whole amount of material contained in the 
principal European collections. I thus examined nearly 10,000 specimens of Lucanide, 
and about 1000 specimens of Passalide (a group which was formerly erroneously 
included in the Lucanide), and investigated the constancy or inconstancy of their 
morphological characters. 
The following are the conclusions at which I have arrived respecting the variability 
which exists within the limits of a single species :— 
Although the male and female form a single whole, constituting one species, both 
sexes vary, but in different directions. The male varies much more in size, shape, and 
colour than the female, which remains more constant to the type, so that the females 
even of distinct genera are very similar, and are frequently very difficult to separate 
from one another, while their males are often very distinct. 
Female. The females are often remarkably different from the males, both in form 
and size. They generally agree with them in colour; and in cases where they are 
differently coloured, it is much more difficult to refer them correctly to the males. 
Examples: Odontolabis stevensi (Pl. XC. figs. 1-4), O. gazella (=O. bicolor 3, and 
O. gazella 2 ) (P\. XCVI. figs. 10, 11). 
In Cyclommatus the females of the majority of the species are dark-coloured, and 
are brown or metallic like the males; but the females of C. mniszechi, Thoms., and 
C. strigiceps, Westw., have bicolorous elytra. 
In Odontolabis brookeanus the colour of the elytra is variable (Pl. XCV. figs. 16-18). 
In small specimens of 0. lacordairii (Pl. XCIV. fig. 7) the red spots on the prothorax 
are wanting, and the canthus round the eyes varies in width. 
The form and size of the prosternal process is variable, and the number of spines on 
the outer side of the front tibiz also varies. But the size of the whole insect is the 
most variable character. 
Male. The males of the same species vary much more than the females :— 
(1) In the total size. 
(2) In the size, form, and teeth of the mandibles (Cladognathini and Odontolabini). 
(3) In the number of apical lamelle of the antenne. In some cases this is an important 
family character, but in Lucanus cervus' these vary in form and size, and there 
may be either 4, 5, or 6. 
(4) In the shape of the head. 
(a) Enormous development of the frontal ridge in Homoderus mellyi, Parry *, and 
1 Compare Abeille de Perrin, Ann. Soc. Ent. France (4) vii. p. 70 (1867). 
2 Compare H. Deyrolle, Ann. Soc. Ent. France (4) iy. p. 316, pl. iv. figs. 2,2a (1864) ; Parry, Trans. Ent. 
Soc. Lond. (3) ii. pl. xi. fig. 6 (1864); and Westwood, op. cit. (3) i. p. 437, pl. xvi. figs. 7, 8 (1863). 
