412 DR. F. LEUTHNER ON THE ODONTOLABINI, 
(ii.) Group of O. stevensi. (Plate XC.) 
The connection between the black male and the bicolorous female of 0. stevensi from 
Celebes was long suspected, but not proved until the discovery of the closely allied 
O. duivenbodii, in which the elytra are tricolorous in both sexes, and which occurs in the 
neighbouring island of Sangir. But the latter coloration is not exactly new, for it arises 
from the disappearance of the black pigment on the middle of the elytra, as in Neolu- 
canus cingulatus (2). Notwithstanding the differences in the prothorax (figs. 7, 8), the 
males exhibit much similarity in the structure of the head, and in the form of the 
mandibles; but in the largest forms (figs. 5, 6) the latter are differentiated, so that in 
the latest evolved species they are apparently more simplified than the parent species, 
and resemble those of O. alces, var. dux. 
(iii.) Group of O. burmeisteri. (Plates XCI., XCII.) 
This group comprises a very natural assemblage of species—(1) 0. sinensis (China), 
(2) O. mouhoti (Siam), (3) O. cuvera (N. India), (4) O. delesserti, and (5) O. bur- 
meistert (Travancore). Their common origin is palpable, both sexes being equally 
differentiated. Their differences, however, depend more on colour than on form. 
In the group of 0. alces the uniform black colour of the elytra, especially in the 
females, renders their determination a task of great difficulty; but in the present 
group it is more especially the females which enable us to separate the species satis- 
factorily by their characteristic and constant markings. In O. sinensis (Pl. XCI. fig. 4) 
there is only a narrow reddish-brown border to the elytra, both above and below. In 
O. cuvera (Pl. XCI. fig. 10) this is pale brownish-yellow, and much broader, but the 
under-surface of the rim of the elytra is always black. This is also the case in the 
much larger female of 0. delesserti (Pl. XCII. fig. 4), whereas in the female of O. bur- 
meisteri (Pl. XCII. fig. 9), in which the black portion of the elytra is still narrower, 
the under-surface of the recurved rim of the ‘elytra is again yellow, as in O. sinensis. 
The male and female of each species agree in the colour and markings of the elytra, but 
the under-surface is frequently different. Thus it is in 
Male. Female. 
Ossinensig” 4. 4, ~ «yellow ge.) eee) su yellow. 
Os mothOli.o 4) Sisk bs che wyellows REbetae Ene Noi 
On outerdsiie| -aat-oy'o\ nly lores: AF teeta ees 
O..delesserti , 455 « » black OMe aise > pleek 
O. burmeistert «4.4 | yellow 5.2 + + + yellow. 
Whether this enables the sexes to recognize each other, as it enables us to separate 
the species, cannot be decided. 0. sinensis (Pl. XCI. figs. 1-3) and O. cuwvera (figs. 7-9) 
agree in the forms of the male mandibles, and in the strong spines of the front tibie. 
