Hardenberg—Studies in the Trophi of the Scardbaeidae . 549 
(2) the influence of the food habits on the variation of the 
month-parts; (3) the amount of these variations and their 
taxonomic value, if any. 1 
The subject will be divided into four parts:—(1) General 
discussion of the mouth-parts of Coleoptera; (2) Description 
of the mouth-parts of Copris Carolina Linn., as a standard for 
comparison; (3) Description and discussion of the mouth- 
parts of representatives of different genera; (4) Summary 
and conclusions. 
The material used was taken from the duplicates of Profes¬ 
sor Marshall’s collection, supplemented by specimens from my 
own cabinet. The specimens were boiled in caustic potash 
solution; the mouth-parts dissected out, and mounted for mi¬ 
croscopic examination. Owing to the thickness and peculiar 
shape of some of the trophi, especially the mandibles, consider¬ 
able difficulty was at first experienced in making satisfactory 
preparations. They were for the most part mounted in Can¬ 
ada balsam, without a cover glass; the object was first cemented 
to the slide with a little balsam, then the slide inverted and 
allowed to dry under a bell jar, successive drops of balsam 
being added from day to day until the whole object was cow 
ered. In some cases, especially when studying the labial 
structures, the object was examined in glycerine, and the parts 
were drawn in situ. The drawings were all made with a 
camera lucida, but, owing to the minuteness of some parts and 
the comparatively large size of others, the magnification is 
not the same in all cases. This is indicated, however, for 
every figure. 
The treatment to which the parts were subjected made any 
histological examination of sense-organs impossible ; the pres¬ 
ence or absence of these was judged by general external ap¬ 
pearance. Such a thorough examination as would be necessary 
ilt was thought at first that the treatment of another interesting 
subject in connection with this could he attempted, namely, in how far 
a classification based on the mouth-parts would correspond with the 
present arrangement of the genera and species in this order; but, al¬ 
though some important data were gained, the number of species ex¬ 
amined was too limited to warrant any definite statement for the 
present. 
