Hardenberg—Studies in the Trophi of the Scardbaeidae. 587 
the leaf-chafers into several minor divisions which, though 
sharply separated by their external appearance, have similar 
habits, so that the mouth-parts do not show such a distinct 
division. We can distinguish only two groups, the leaf-chafers 
proper (A and C), and the pollen-eating forms (D) ; the 
rose-bugs (B), which live on the petals of flowers, form an 
intermediate group. 
The leaf-chafers proper ( Hoplia, Dichelonycha, Diplotaxis, 
Lachnosterna, Anomala, Pelidnota, Cotalpa, Cyclocephala, 
Ligyrus, Xylorodes') show in their month-parts the following 
characteristics: 
a . The epipharynx shows a considerable modification; in the 
first members of the group it has a membranous median area, 
which changes gradually until in the last member it has be¬ 
come entirely chitinized. With this increased chitinization 
goes a corresponding decrease in the development of the sen 
sory apparatus. 
b. The mandibles show a great development of the molar, 
and the galea usually ends in strongly chitinized teeth. The 
lacinia is correspondingly reduced and represented by a fringe 
of hairs, extending from the base of the apical teeth to the 
molar. 
c. The labial structures are decidedly different from those 
of the scavengers. The mentum is pushed in over the sub- 
mentum; the inner labial lobes are very much reduced or want¬ 
ing; the hypopharynx has entirely disappeared, and the an¬ 
terior and posterior plates of the sub-mentum are nearly equal 
in size. 
In group D, the flower-beetles ( Euphoria , Allorhina, Osmo - 
derma, Trichius, Valgus ), the mouth-parts again become less 
chitinized and are covered with long, stiff hairs for collecting 
pollen. 
a . The epipharynx becomes more specialized and prominent, 
and in some species again forms a free fold of the roof of the 
mouth. 
b. The molar is much reduced in the mandible, which has 
both galea and lacinia long and slender, the former ending in 
