Hnrdenberg—Studies in the Trophi of the Scarabaeidae. 551 
The under side of the labrum is covered by a membrane, the 
epipharynx (Packard, 7), which contains the organs of taste. 
It corresponds in extent to the clypeus and labrum, posterior¬ 
ly merging into the dorsal wall of the pharynx; the suture 
which separates the labrum from the clypeus does not involve 
the epipharynx (7). This would seem to show that this or¬ 
gan is not merely the under side of the labrum, but has an 
independent origin; it really is a fold of the membrane which 
forms the roof of the mouth. Besides the sense-organs, the 
epipharynx is covered with hairs or setae, which are classified 
by Packard under two heads: 
a. The normal hairs, arising from a definite cell, and 
which are either simply defensive, guarding the sense-cups of 
the sensory fields in which the sense-cups are borne, or they 
are simply tactile hairs. 
b. Soft, flattened, often hooked hairs, cylindrical toward 
the end but arising from a broad, triangular base, comparable 
to the gathering hairs described by Cheshire on the bee’s 
tongue. 
We shall find that the epipharynx is present and recogni¬ 
zable in nearly all of the species of Scarabaeidae which were 
examined, and that it shows an instructive series of stages in 
reduction. 
Mandibles. These are used for very different purposes, 
being either adapted for cutting, tearing and crushing ,the 
food, or for defense; in Cetonia et al., they are used as a 
brush for collecting pollen. They are usually opposed to each 
other at the tip, or even crossed, but in the Coprini and in 
most of the Scarabaeidae the tips are separated and the bases 
alone are opposed, strongly chitinized and ridged, the right 
one being convex, the left one concave, and the two fitting ac¬ 
curately into each other. Although the mandible is general¬ 
ly a strongly chitinized single piece, it really consists of four 
(possibly more) sclerites which are well shown in some of the 
Scarabaeidae. In some species of Coleoptera ( Passalus cor- 
nutus) we find a movable piece at the base of the mandible. 
This is the prostheca of Kirby and Spence (4), and is consid- 
