Hardenberg—Studies in the Trophi of the Scarabaeidae . 583 
expect to find a corresponding increase in tlie sense-organs of 
the labial structure. This is the case; the entire dorsal sur¬ 
face of the mentum is covered with sense-papillae, and every 
vestige of hairs has disappeared. The absence of pollen-gath¬ 
ering hairs on the maxilla, the more highly developed sense- 
organs, and the more prominent molar of the mandibles, all 
point toward a difference in food habits between this and other 
members of the same group, this species not living entirely on 
pollen but in part on the flowers themselves. 
Valgus squamiger Beauv. (PL XXXIII, Figs. 100-102). 
Although nothing could be learned about the food-habits of 
this, the last member of the series, its mouth-parts show that 
it is a true pollen-eating species. 
The epipharynx (Fig. 100) shows the long, stiff, pollen- 
gathering hairs covering its lateral portions, while in the me¬ 
dian area posterior to them are situated a small number of 
sense-cups. 
The mandibles (Fig. 101) here also show a rudimentary 
molar, a conspicuous lacinia and a slender, slightly chitinized 
galea, the tip of which is membranous and is fringed with 
short, soft hairs. 
The maxtillae (Fig. 102) are shorter than those found in 
Euphoria, with the palpi stronger and more prominent. The 
galea and the lacinia are very thickly covered with long, stiff 
hairs for gathering pollen. 
The labial structures are essentially the same as those de¬ 
scribed for Euphoria and need no special discussion. 
Summary and Conclusions. 
The present study of the mouth-parts of the Scarabaeidae 
has brought out many points of interest, some of which may 
be discussed under the following headings: 
I. Division of the order into groups, and the general 
characteristics of the mouth-parts in each; 
II. The evolution shown throughout the order from types 
which are morphologically lower but which function 
ally show a higher specialization, to those in which 
these two conditions are exactly reversed. 
