572 Wisconsin Academy of Sciences , Arts, and Letters. 
its palpi has been pushed in over the distal end of the sub-men-- 
turn, and what is seen projecting distad from the sub-mentum 
(looking at it from the ventral side) is only a part of the men- 
tum. In the case of Hoplia trifasciata only a small portion 
of the mentum is visible from beneath, the greater part of it 
lying on top of the sub-mentum. The front and lateral edges 
only are chitinized, and the membranous enclosed area is de¬ 
void of sense-cups, but furnished with lateral rows of long, thin 
hairs wdiich converge posteriorly. 
Dichelonycha elongata Fab. (PI. XXXII, Figs. 55-58). 
Epipharynx (Fig. 55). Here this organ is still more reduced 
and almost entirely corneous; only a few scattered hairs and 
papillae are left to indicate its original function. The epi¬ 
pharynx is reduced, not only in specialization, but also in ex¬ 
tent, and has become very much shortened. 
Mandibles (Fig. 56). These are much more chitinized; 
they are, in fact, almost entirely corneous. The molar has 
greatly increased in size; the apical tooth of the galea has be¬ 
come broader and the lacinia shorter and much reduced. The 
large molar, the broad apical expanse of the galea and the 
heavy chitinization give to the organ a strong, compact appear¬ 
ance. 
Maxillae (Fig. 57). The galea is well developed and 
strongly chitinized, while the lacinia is much reduced, having 
lost its hairy covering and become a thin, chitinous plate. 11 
forms part of the dorsal surface of the organ and extends to 
the median edge where it is deflexed and forms the internal 
margin of the maxilla, so that when viewed from the vential 
side the lacinia appears as a thin line along the inner edge of 
the sub-galea. 
The maxillary palpus is very long, and the palpifer bears 
two conspicuous, long, stiff setae. 
Labial structures (Fig. 58). These are similar in position 
to those of the preceding species, except that the inner lobes of 
the labium are still distinguishable. They appear as mem¬ 
branes, separated from each other along the median line for a 
short distance from the distal edge, and are sparsely covered 
