THE PSELAPHIDA OF NORTH AMERICA, 

A MONOGRAPH BY 
EMIL BRENDEL, M. D., ann H. F. WICKHAM. 
In preparing this monograph the authors hope to aid stu- 
dents of this large and interesting family, by sufficiently minute 
descriptions and synoptical tables, to recognize any species 
known to the fauna of the United States and British America, 
and to see the affinities of American species to members of 
this family in other lands. 
Far from believing this to be a perfect work, the authors 
submit it as a contribution liable to future revision. Even if 
the ideas herein set forth are not accepted, the present com- 
pilation of hitherto scattered descriptions will, it is hoped, be 
of value. 
The descriptions of early authors were sufficiently minute 
to differentiate the small number of species then known. At 
present many of those descriptions are applicable to quite dif- 
ferent forms, and synoptical tables based upon the old descrip- 
tions have become an impossibility. Up to the time of Jno. 
L. Leconte, the number of species was very limited. In 1817 
Say described but three species — Tmesiphorus carinatus, 
Bryaxis dentata and Batrisus riparius. Aubé in 1834 added 
three or four, some not now recognizable, and Motschulsky in 
1845 two or three more—jll described. Leconte followed 
with eighty-four species. 
Although the number of descriptions is now quite consider- 
able, their insufficiency has been a great difficulty, and ocular 
comparison of specimens is often necessary to determine a 
species. By exactness of description and by carefully drawn 
figures we hope to relieve the student henceforth from the 
necessity of such direct comparison. 
