COMPARATIVE STUDIES IN THE TROPHI OF THE 
SCARABAEIDAE. 
(With Plates XXX-XXXIV.) 
C. B. HARDENBERG. 
The mouth-parts of the Coleoptera, although known in a 
general way and to some extent used in classification, have not 
yet been studied as thoroughly as might be desired; of many 
species the mouth-parts are tacitly assumed to be in accord 
with the general shape of those of their nearest allies in the 
taxonomic division. If we consider, however, that the insect 
is directly dependent upon its food for its existence, and that 
the habit of acquiring its nourishment will directly affect the 
form of its mouth-parts, it becomes evident that a difference 
in food habits among members of the same natural group will 
cause a corresponding difference in their mouth-parts. 
It was with a view of ascertaining these variations that the 
present study was begun. One great natural group was selected, 
the Scarabaeidae, or Lamellicorn beetles, in which are classed 
together insects of very different food habits,—some living on 
very soft material, like the dung beetles, others on dry animal 
matter (skin beetles), others again on leaves (June beetles et 
al.), and some on pollen (Cetoniae). We may therefore nat¬ 
urally expect to find a considerable amount of variation. 
The study was undertaken for the purpose of ascertaining 
the following data: (1) the general degree of specialization 
in the order of Scarabaeidae and of departure from the as¬ 
sumed primitive insect type as presented by the Orthoptera; 
