AQ Prof. J. C. Schiddte on the Tunnelling Coleoptera. 
the terminal joint of both pairs of palpi presented a rather 
peculiar structure. In dry specimens this betrays itself by 
the joint being somewhat broader than usual; and on the 
under surface a deep spoon-shaped cavity is observable. In 
fresh specimens, or such as have been boiled for examination, 
the hard chitinous integument seems to-be wanting in this spot, 
and to be replaced. by a soft membrane, closely covered, as if it 
were paved, with small black polygonous chitinous warts, pretty 
regularly disposed in quincunx. It can scarcely be doubted 
that this is an organ of sense, a secondary palparium; and a 
dissection of the internal sexual organs shows that the indivi- 
duals possessing this peculiarity are all males. Hitherto no 
external marks of distinction between the sexes were known; 
but these supplementary inferior palparia are found in the males 
of all species of Dyschirtus and in many exotic species of Clivina, 
though they are wanting in the males of Clivina fossor. 
The characters available for the distinction of species are not 
very many. Originally authors were almost confined to the 
variations of the external teeth on the tibie; Erichson added 
(Kafer d. Mark Brandenburg) the varying extension of the mar- 
ginal strie of the elytra; in ‘Danmarks Eleutherata’ I pointed 
out some additional characters derived from the shape of the 
clypeus; whilst Thomson, in ‘ Skandinaviens Coleoptera,’ drew 
attention to the marginal strie of the pronotum, which some- 
times are wanting, and, where they exist, extend to a varying 
distance from the posterior corners. ‘Two new characters may 
be derived from the different size of the supplementary palparia 
on the maxillary palpi of the males, and from a small difference 
in the outline of the ligula (or, rather, fulerum ligule). By 
combining these characters, the species may be grouped with satis- 
factory precision. But within the pale of each of these groups the 
species are so closely connected that it is exceedingly difficult to 
distinguish them except by a set of characters which are not 
always as sharp as could be desired; and one is often tempted 
to look upon many reputed species as mere local variations. 
But this same uniformity is observable also in other genera of 
Scaritini, and is, upon the whole, of frequent occurrence in 
Arthropoda which dig or burrow in the ground, within such 
genera as have a very wide geographical distribution. If, 
then, those species of Dyschirius which dig their tunnels on the 
shores of the Ganges, or in the salt-moors of Tranquebar, and 
along the rivers of America, when carefully examined, differ as 
little from our indigenous species as these latter do from one 
another, we must be content to leave the matter as it is, in spite 
of the dearth of specific characters. 
