Hardenberg—Studies in the Trophi of the Scarabaeidae. 571 
pharyngeal structures. These are, however, much reduced, 
and laterally we find a number of tactile hairs, while the me¬ 
dian sense-area bears only a small group of flat, round papillae. 
Mandibles (Fig. 49). These are very thoroughly chiti- 
nized, so much so that the homology of the parts has become 
entirely obscured and cannot be traced with any degree of cer¬ 
tainty. Their outer surface, as is the case with all the mouth- 
parts of this beetle, is thickly covered with short, thick, stiff 
hairs, evidently adapted for brushing and scraping. 
Maxillae (Fig. 50). Here again the lacinia ends in a tooth 
and bears a digitus, which is here double-toothed. Stiff hairs 
are intermingled with these teeth. 
Labium (Fig. 51). The sub-mentum has its anterior and 
lateral margin folded in, and its normally anterior margin 
bears the mentum with its palpi and lobes. The labial lobes 
are represented by a thin membrane which bears two rows of 
hairs. These may indicate the line of fusion of outer and 
inner lobes. The hypopharynx has almost entirely disap¬ 
peared. At the posterior end of the lobes there is only one 
row of sense-cups, and in front of these are two pairs of flat, 
round papillae. 
Hoplia trifasciata Say (PI. XXXII, Figs. 52-54). 
Epipharynx (Fig. 52). This shows in its form and structure 
a close resemblance to the corresponding organ of Trox scut el- 
laris ; in fact, nearly all the following species show the lateral 
and distal edge of the labrum turned in and chitinized, the 
space enclosed by them being covered with a membrane, the true 
epipharynx. In this species both the labrum and the epiphar¬ 
ynx are very much shortened. The membranous area is fur¬ 
nished with a few sense-cups in the center and is covered later¬ 
ally with long, stiff hairs. 
Mandibles (Fig. 53). These are strongly chitinized and 
show a well developed molar furnished with strong ridges. 
The galea forms a single apical tooth; the lacinia is also 
present and recognizable by its characteristic hairs. 
Labial structures (Fig. 54). Here the conditions are dif¬ 
ferent from those previously described. The mentum with 
