568 Wisconsin Academy of Sciences, Arts , and Letters . 
Labium (PI. XXXII, Pig, 35). The labial structures show 
a decided change and a reduction. The mentum is no longer 
turned over and lying on top of the sub-mentum, but is now 
in front of this piece. It is very small, however, and being 
pushed somewhat back over the sub-mentum, it is easily over¬ 
looked. As a result of this change in position, the labial palpi 
no longer arise above, but distad from the sub-mentum. 
The palpi are three-jointed and slender. The lobes are 
both present; the outer one is a slightly chitinized plate, sparse¬ 
ly covered with stiff hairs; the inner lobe is bmall and mem¬ 
branous. Xo hypopharynx could be found; the hairy struc¬ 
ture on the membranous floor of the mouth corresponds neither 
in structure nor in position to a hypopharynx, but is similar 
to that structure which we find posterior to the epipharynx on 
the membrane forming the roof of the mouth. 
The whole sensory apparatus of this insect has been reduced, 
and those hairy, slightly chitinized parts of the membrane just 
referred to seem to be the remnant of the large hypopharyn- 
geal structure. 
Bolboceras farctus Fab. 
The epipharynx (PI. XXXI, Fig. 36) is in general the same 
as in Bradycinctus. 
The mandibles (PI. XXXII, Fig. 37) are more strongly 
chitinized, and the galea has two teeth at the apex. The lacinia 
bears a divided tooth; at its end and from here inward the 
usual hairy fringe is present. Xo trace of a conjunctivus 
could be made out. 
The maxilla is similar to that of the preceding species, ex¬ 
cepting that the digitus of its lacinia has become longer, more 
curved and forked at the end. Stipes and palpifer are pro¬ 
vided with very long tactile hairs. 
Labium (PI. XXXII, Fig. 38; PI. XXXIV, Fig 4). The 
mentum here is similar to that already described for Bradycinc¬ 
tus ferrugineus. The labial lobes, however, are thoroughly 
chitinized, the outer lobes fused, and only rudiments of the in¬ 
ner lobes are visible as slight projections. The fused chitinized 
outer lobes are very easily mistaken for the mentum, but the 
