DR. F. LEUTHNER ON THE ODONTOLABINI. 391 
trispinose, with two deep concavities; while in the small males the sides are 
convex, as in the females (comp. 0. alces, Pl. LXXXIX. figs. 1, 7, and 
O. lacordairii, Pl. XCIV. figs. 1, 2, 5, 6, &c.). 
(q) The breadth of the prothorax often varies, which considerably affects its out- 
line, as, for instance, in O. bwrmeisteri (comp. Pl. XCII. figs. 5, 6). 
(2) In many species the form of the prosternal process is also variable. 
(6) In the elytra. 
(i) These are sometimes strongly convex and sometimes flattened (as in 0. lati- 
pennis). 
(k) The sculpture. In the Dorcini, for example, Eurytrachelus titan, Boisd., 
E. tityus, Hope, and Dorcus dehaani, Hope, D. parryi, Thoms., and D. musimon, Gené, 
the large males have smooth elytra; and the small males ridged elytra, like the females 
(pterygo-dimorphism). 
(2) Coloration (0. wollastoni, Pl. XCIII. fig. 6, 7), &c. 
(7) In the shape and armature of the front tibiz (a specific character). 
In the Odontolabini large (telodont) specimens have generally fewer spines than small 
ones (in O. burmeisteri, O. alces, &c.). 
(8) In the armature of the four hind tibiz (a family character). 
In Cladognathus giraffa and C. confucius the middle spine of the hind tibiz is wanting 
in small males. ‘This is likewise the case in some species of the genus Agus. 
Hence it follows, as an unavoidable conclusion, that every morphological character 
proves, when thoroughly tested, to be variable in one species or another, a result of 
great importance to systematic morphology. 
(2) Variability and Polymorphism in the Mandibles. 
Every one is well acquainted with our indigenous Stag-Beetle (Lucanus cervus) and 
with its very different female. This species varies so much in size that the older 
authors naturally regarded the small males as belonging to a different species, which 
they called LZ. capreolus, Fabr. But early in the present century, Koechlin, an entomo- 
logist residing at Mulhouse, having found a large number of specimens in one locality, 
endeayoured to show that the small specimens were ‘‘not a specially created species,” 
but only a slight variety of the large ones; and this view has been accepted by later 
entomologists until the present day’. 
If a European entomologist were to collect a long series of males of L. cervus for the 
purpose, he would be able to satisfy himself that they vary chiefly in size, and that the 
mandibles of the small males are formed like those of the large males; the only dif- 
ferences being that the terminal fork is truncated, and that the occipital crest is obsolete. 
This would lead him to conclude that the small males are only imperfectly developed 
specimens. 
1 Correspondance entomologique, 1823. Remarques sur Je Lucane, ou Cerf Volant, 
