STAPHYLINIDA. 145 
Fam. STAPHYLINIDA. 
Subfam. ALEOCHARIN A. 
This subfamily is the most extensive and the least studied of those comprised in the 
family ; and its treatment in a satisfactory manner is a matter of extreme difficulty. Of 
the vast number of extra-European forms that no doubt exist but little is yet known, 
even the North-American forms having been hitherto neglected by entomologists. If we 
add to this the fact that the Aleocharine are nearly all minute or quite small insects, of 
fragile and loosely articulated structure, with softer chitinous envelope than is usual in 
the Coleoptera, it will readily be comprehended that the classification of the components 
of the subfamily has scarcely commenced. The large number of species and genera 
at present registered in the subfamily (amounting probably to 2000 species and consi- 
derably more than 100 genera) renders it, however, advisable that some method shall 
be adopted in their arrangement, if only with the object of facilitating reference and 
of saving time; and I shall accordingly make use of that recently proposed by Mulsant 
and Rey for the species of France, in the ‘ Histoire Naturelle des Coléoptéres de France, 
Brévipennes, Aléochariens,’ introducing, however, some modifications in order to render 
it more simple. In this scheme the number of joints in the tarsi is considered superior 
in importance to the condition of the trophi, on which Erichson and Kraatz, the 
principal previous write’ on the family, chiefly based their genera and arrangement. 
It would be out of place to discuss here the comparative claims of these two methods 
to superiority; but it is clear that the advantages offered by the tarsal system, as 
regards facility of verification and simplicity of definition, are very great, and give it, 
as a provisional method, preponderant importance. I have avoided as far as possible 
the establishment of new genera; but yet the number proposed in the subfamily will 
be found not inconsiderable; and as it will be remarked that some of the terms I have 
used in defining them are new, I may here give a word or two of explanation about 
them. On examining some of the Staphylinide, such, ¢.9., as a large Xantholinus, 
it will be observed that the middle coxe are almost without true acetabula; this part 
of the limb, in fact, merely reposes on the outer surface of the breast, which is more 
or less vaguely impressed for its accommodation. In other forms, e.g. Aleochara, it 
will be found, on the contrary, that the coxa is imbedded in an abruptly defined cavity 
surrounded entirely by a well-marked raised margin. Between the extreme forms 
mentioned a large number of intermediate stages exist, and in the Aleocharine offer a 
satisfactory and readily observed method of differentiating the genera. When these 
two cavities exist entirely surrounded by a raised margin, as in Aleochara, I have used 
the expression “cavities complete :” the completion is effected on the inner side by a 
prolongation of the mesosternum between the cox meeting a prolongation from the 
metasternum; these prolongations may be called the mesosternal and metasternal 
BIOL. CENTR.-AMER., Coleopt., Vol. I. Pt. 2, May 1883. UU 
