xX INTRODUCTION. 
of our genera have a very wide distribution. On the other hand, I have found it 
necessary to establish a large number of new genera for our species; and many of these 
certainly occur in other regions, though the fact of their doing so has not at present 
been actually ascertained. 
I may, however, I think, say that, in the case of genera with a large number of 
species and a very wide distribution, the forms found in our subregion are much more 
nearly allied to those of South than they are to those of North America. 
I am therefore quite inclined to agree with the opinion expressed by Mr. Bates, 
after his examination of the Geodephaga and Longicornia, that our subregion is 
essentially Neotropical. At the same time I very much doubt whether Northern 
Mexico can be considered to belong to it; and I anticipate that the best line of division 
between the Nearctic and Neotropical regions will be found, not at the political 
boundary between Mexico and the United States of North America, but rather some- 
where about the line of the Tropic of Cancer, or, more probably, a little to the north 
thereof. 
The Staphylinide brought from the tropics previous to the commencement of this 
work contained a very large proportion of species remarkable for their comparatively 
large size, bizarre form, or brilliant colours; but it is now clear to me that this is very 
largely due to imperfect collecting. Indeed, one of the striking facts in connection 
with the collections of this family that our Editors have brought together with such 
success, 1s the very large number of minute and obscure insects contained in them ; 
there are a fair number of large, remarkable, or beautiful forms, but these are few in 
comparison to the small and inconspicuous species, so that it can scarcely be said that 
the Central-American Staphylinide are on the average larger or more brilliant than 
those of Europe. 
November 1887. 
