566 Wisconsin Academy of Sciences, Arts, and Letters. 
is fused with the end of the galea; we cannot say where one 
ends and the other begins, only the comb-like fringe of hairs 
showing that it is the lacinia with which we have to deal. 
Labium (Fig. 31). The inner lobe is sparsely covered 
with scattered saber-shaped hairs; where it joins the hypo- 
pharynx it changes into an oval, cushion-like structure, thickly 
covered with slender, pointed cones. The hypopharynx is 
here again a thin plate, broadened in front and covered with 
fine, soft, moderately long hairs. 
We see in this natural group of the dung beetles a grea: 
similarity in the mouth-parts, as was to be expected. Sum¬ 
ming up the characteristics, we have: 
1 . A large, membranous epipharynx, with well-developed 
sensory area. 
2 . Mandibles which show that they were originally com¬ 
posed of a number of sclerites, the homologies of which can be 
traced to those of the maxillae; their anterior parts are mem¬ 
branous, with a pair of grinders or molars placed at their pos¬ 
terior ends. 
3. A labium in which the mentum is turned in over the 
sub-mentum, with the labial lobes membranous, and galea and 
lacinia generally fused; the inner lobes at their junction pass 
over into the hypopharynx; the latter part and the labial lobes 
show a great amount of variation in the different species, 
though individual differences were found to be immaterial. In 
general we have two types: 
a. The hypopharynx is well-developed and bears peculiar¬ 
ly shaped sensory hairs; the inner lobes bear almost exclusive¬ 
ly long, slender tactile hairs. 
b. The hypopharynx is clothed with long, slender hairs 
which are here non-sensory, this function being taken over by 
the median pari; of the inner lobes, which bear peculiar struc¬ 
tures. 
4. A loosely developed elastic swallowing apparatus, the 
fulcrum hypopharyngeung the structure of which was not, 
however, examined in detail. 
