H ardent erg—Studies in the Trophi of the Scarabaeidae. 555 
das sich das zugehorige Ursegment am Embryo nicht findet' 
wir diirfen docli nicht fiir eine Tatsache halten, was wir nicht 
gesehen haben.” 
At the present stage of our knowledge it is impossible def¬ 
initely to settle the question of the origin of the hypopharynx, 
but it probably represents a fold of the membranous floor of 
the mouth, just as the epipharynx originates as a fold of the 
roof of the mouth. 
According to Comstock (1), the epipharynx and hypophar- 
ynx are rarely both developed in the same insect, except in 
Hymenoptera; in the species of Scarabaeidae, however, they 
are for the most part either both present or both wanting, but 
the hypopharynx is never conspicuous. 
The Mouth-Parts of Copris Carolina Linn. 
Smith (8) was the first to study the mouth-parts of this in¬ 
sect and to attempt to homologize the parts of the mandibles 
with those of the maxillae. His statements, though mainly cor¬ 
rect, proved to be erroneous in some points, as I hope subse¬ 
quently to show. 
In this insect (and in the whole group of dung-beetles in 
general), we find a very peculiar development of the mouth- 
parts, which accords with its food habit. Functionally they are 
very much specialized, while morphologically they represent a 
low stage in the evolutionary scale. 
The epipharynx (PI. XXX, Pig. 1) consists of a large mem¬ 
brane forming the roof of the mouth. Two lateral areas are 
separated from the median part by a row of stiff, bristle-like 
hairs which are continued sparsely on the front margin, while 
their surfaces are densely covered with short, fine hairs, these 
also covering the posterior rwo-thirds of the central portion. 
The regular arrangement of these hairs makes it appear as if 
the lateral parts of the epipharynx were curved inward and 
downward (as is claimed by Smith to be the case), but no evi¬ 
dence in favor of this view could be found; the hairs are not 
situated on a free edge, and a transverse section through the 
epipharynx does not show the conditions which we should ex- 
