Ha/rdenberg—Studies in the Trophi of the Scarabaeidae. 585 
c. Maxillae in which the galea is somewhat quadrangular, 
usually membranous, and thickly clothed with fine hairs. 
d. Labial structures which show both the outer and inner 
lobes present but generally fused, those of the one side separate 
from and not fused with those of the other side. 
e. A mentum which with its palpigers is turned over on 
the sub-mentum, so that the palpi seem to arise above (dorsad 
from) the sub-mentum. 
/. A sub-mentum, consisting of an anterior, smaller, and a 
posterior, larger, plate. 
The scavengers are sub-divided into four groups: 
A. The tumble-bugs ( Canthon,, Copris, Choeridium , On 
thophagus, Phanaeus). 
B. The Aphodian dung-beetles ( Aphodius ). 
C. The earth-boring dung-beetles ( Bradycinctus , Bolbo- 
ceras, Cloeotes , Geotrupes). 
D. The skin-beetles ( Trox ). 
Of these four groups, the Aphodians are not entitled by the 
shape of their mouth-parts to separate rank, but should be 
included in the first group with the tumble-bugs. 
This group (A and B) would then be characterized by: 
a. A large epipharynx which is attached to the under side 
of the clypeus by a more or less prominent supporting rrch, 
and in which the gustatory area forms a median club-shaped 
thickening (broadening posteriorly in the Aphodians) bounded 
laterally by one row of tactile hairs, which fringe the edges of 
the turned-in lateral parts. 
b. Mandibles which show a well developed, ridged molar, a 
leaf-like membranous galea with fringed edge, a long, mem¬ 
branous lacinia and a conspicuous conjunctivus. 
c. Maxillae in which the galea is sub-quadrangular, thickly 
clothed with fine hairs (as is also the lacinia), and is connected 
to the sub-galea by a conspicuous, Y-shaped, chitinous rod, 
which may represent the proximal segment of the galea. 
d. A distinct hypopharynx with labial lobes, the outer lobe 
of which is slightly chitinized and fused with the more or less 
