414 DR. F. LEUTHNER ON THE ODONTOLABINI. 
are rounded, and less strongly curved. The diminution in the spines on the front tibie 
in O. delesserti proceeds further in O. burmeisteri, and they may even disappear 
entirely in the telodont form. This and the great variability of the extreme form, 
combined with geological facts, render it probable that we are dealing with a younger 
offshoot in which the characters have not become so stable as in the northern species. 
The occurrence of the two last species in the same localities may lead to the 
production of hybrids, for I have seen individuals which it was difficult to assign to 
either species. ‘This applies both to the small males and to female specimens. 
The differences between the species of this group are so slight that Prof. Westwood 
regarded them as only geographical varieties. A large amount of material has enabled 
me to separate them (comp. anted, p.9). But it is obvious that continental species can 
never be so sharply defined as insular species. 
The great similarity of the females and the uniform character of the coloration of 
the elytra bridge over the gap between the continental Indian durmeisteri group and 
the insular wollastoni group. 
(iv.) Group of O. wollastoni. (Plates XCIII., XCIV.) 
The males of this group are distinguished by the luxuriant development of their 
mandibles, and by the strongly marked and coarsely shagreened sculpture of their 
broad heads. The species here admitted are—(6) O. wollastoni, (7) O. vollenhovent, 
(8) O. ludekingi, and (9) O. lacordairii, which inhabit Malacca, Sumatra, and Borneo. 
The two first species agree in the shape of the mandibles, and are only distinguished 
by their different colour. In 0. wollastoni, which occurs in Malacca and Sumatra, 
the black triangular patch on the elytra is broad, nearly as in O. cuvera, but is less 
constant in form, and either extends in a point to the tip of the elytra (Pl. XCIII. 
figs. 5, 6), or it is broader (fig. 7), and ceases suddenly before the tip (in Parry’s type) as in 
O. sinensis (Pl. XCTI. fig. 1¢). In the Bornean O. vollenhoveni (Pl. XCIII. figs. 1-4) 
it is reduced to a narrow black stripe on the suture; but the head is marked with red 
in the male, which immediately distinguishes it from the preceding species. It occurs 
in south-eastern Sumatra in company with O. lacordairii (Pl. XCIV.). In O. lacor- 
dairii the red colouring is more extended, not being limited to the elytra, but occurring 
on the pectus and on the under-surface of the femora in the male, and on the prothorax 
in the female. 0. ludekingi is distinguished by a narrow pointed stripe on each of the 
elytra; but only a few specimens are known. It occurs in the same locality as the two 
preceding species. Its peculiarly shaped mandibles, of which only small forms are 
known with certainty (Pl. XCIII. figs. 10,11), at once resemble those of O. lacordairii 
(compare Pl. XCIII. figs. 10, 11, with Pl. XCIV. figs. 3, 4) and O. wollastoni, which, 
together with the two differently coloured females of O. lacordairii, render it probable 
that it is a hybrid between O. wodlastoni and O. lacordairii. 
