570 Wisconsin Academy of Sciences, Arts , and Letters. 
ent in connection with the labial lobes; the hypopharynx is 
itself covered with fine hairs, while pointed papillae and sensc- 
cnps are borne on the proximal part of the inner lobes of the 
labium. 
Cloeotus aphodioides Ill. (PI. XXXII, Figs. 46-47, PI. 
XXXIV, Fig. 5). 
Epipharynx (Fig. 53). The epipharynx has become entirely 
corneous. The lateral hairs are disappearing, only a few re¬ 
maining scattered over the surface. A thickened, V-shaped 
median area bears both sense-cups and short papillae. 
Mandibles (Fig. 47). The molars are still distinguishable, 
those of both sides being nearly alike and failing to show the 
convex and concave surfaces hitherto found. There is only 
one apical tooth at the end of the galea, and the lacinia, which 
extends along the inner side of the galea to the base of the 
tooth, presents the characteristic fringe of hairs. A conjunc- 
tivus cannot be made out with certainty. 
Maxillae. The palpi are slender, both galea and lacinia 
well developed. 
Labium (PL XXXIV, Fig. 5). Only the frontal edge of 
the mentum is chitinized; the rest of it is membranous. It is 
here distinctly pushed in over the sub-mentum, and this gives 
to the palpigers with their three-jointed palpi the appearance 
of arising above the sub-mentum. The labial lobes are repre¬ 
sented by a very thin plate, fringed with long hairs and sup¬ 
ported at the proximal part by the hypopharyngeal fulcrum. 
Xo true hypopharynx could be distinguished. 
Trox scutellaris Say (PI. XXXII, Figs. 48-51). 
The members of this genus, the skin beetles, are generally con¬ 
sidered to constitute a group by themselves, and rightly so, for 
in appearance and habits they differ greatly from any other 
group in this order. In structure their mouth-parts show an 
intermediate stage between those of the preceding and those 
of the following group. 
Epipharynx (Fig. 48). The frontal and lateral edges of 
the labrum appear to have been turned in, and the space thus 
enclosed is bridged over by a membrane which bears the epi- 
