454 Mr. WzsTwoop on some new Species of Athyreus, 
The maxille (Tas. XXII. fig. b) also exhibit an interesting structure in 
Athyreus orientalis which I have not seen in other Lamellicorn insects: the 
upper lobe terminates in a broad piece, having a sharp point at its angle 
within the mouth; whilst the lower lobe has two horny processes ; the upper 
one is broadly-truncate and flat, occasionally, as appears from the figures of 
Klug and Curtis, bidentate, but in the species which I examined scarcely 
emarginate; the lower lobe is also flat, but its side is furnished with a series 
of about seven very short thick bristles pressed together, which must evi- 
dently be of peculiar use in the act of mastication. The structure of the 
lower parts of the mouth has been entirely misdescribed by Mr. MacLeay; 
the mentum (Tas. XXII. fig. c), instead of being deeply emarginate, has the 
middle of its fore margin advanced further than the lateral angles; the 
scapes, to which the three-jointed labial palpi ave attached, are slightly pro- 
minent and furnished with short bristles, and the whole of the underside of 
this organ is densely clothed like the rest of the body with very long bristles. 
Other peculiarities of the present genus consist in the very great width of 
that part of the metasternum which occurs between the two middle feet 
(Tas. XXII. fig. d) *, which are thereby inserted much more widely apart, 
than the hind-feet; the very short abdomen, which causes the hind-feet to 
appear as if placed almost at the extremity of the body ; and the great length 
of the hind tibia and tarsi. The figure given by M. Guérin Méneville of 
the underside of the body of Athyreus castaneus, in the * Iconographie du 
Règne Animal, in order to exhibit these peculiarities, is far from correct, the 
metasternum being marked both with transverse and longitudinal lateral 
incisions which do not exist in nature, and which consequently lead to a very 
incorrect idea of the real structure of the underside of the body. 
On comparing these peculiarities of organization with those of Geotrupes, 
the typical genus of the family to which Athyreus has been referred, we are 
bound to admit the correctness of Mr. MacLeay's observation, that this 
‘genus is one of its extreme forms. We here find indeed, in common with - 
Geotrupes, a porrected upper lip and laterally exposed horny mandibles, but 
the structure of the maxille and mentum is very different ; and entomologists 
need not be reminded that it is to these latter organs especially that they 
look for the indication of the nature of the food and the consequent variations 
* Li 
This and the other figures of generic details are derived from Athyreus orientalis. 
