NO. 13 STAPH YLINIDAE BLACKWELDER 3 



jority of specimens are small enough to be suited to examination with 

 the compound microscope ; and, not the least, very little has been 

 known of its fundamental structure and relationships. 



The present study deals with a family which contains nearly 20,000 

 known species. The fact that it would be impossible to study all of 

 these in detail is a very potent additional reason for studying a few 

 representatives as well as possible with the goal of establishing a 

 foundation and working outline of the external morphology which 

 can later be used to support a classification or which may be tested 

 and enlarged by further investigations on additional material. 



It gives me pleasure gratefully to acknowledge the help and en- 

 couragement of Prof. G. F. Ferris, under whom this study has been 

 carried out. I am also much indebted to R. E. Snodgrass, who has read 

 the manuscript and given many very helpful suggestions. 



The Literature on the Staphylinidae 



In a brief review of the literature relating to the family Staphylinidae 

 it is not necessary to go back beyond the works of Erichson in 1839 

 and 1840. Previous to his time most of the work done was a bare 

 description of new genera and species. In the " Kafer der Mark 

 Brandenburg " in 1839 Erichson began the studies that resulted the 

 following year in his masterly volume " Genera et Species Staphy- 

 linorum ". This work contains a fairly complete classification of the 

 family, with keys to genera, and descriptions of all species known at 

 that time. It is undoubtedly one of the masterpieces of early systematic 

 entomology. 



From the time of Erichson there has been a continual stream of 

 descriptions of new genera and species, published in many languages 

 and in hundreds of different periodicals. Many of the most important 

 studies of the staphylinids have been made in connection with large 

 faunal monographs. But by far the largest part of the information 

 published concerning this family has never been assembled in any way, 

 with the one exception of the bibliographic catalogue in the publica- 

 tion of Junk and Schenkling, the " Coleopterorum Catalogus ". The 

 student finds it necessary continually to go to the original publica- 

 tions, and he finds many of the keys for identification unsatisfactory 

 or incomplete. 



Any knowledge of the morphology of this family is exceedingly 

 difficult to obtain from the literature. Most of the discussions are re- 

 stricted to a certain species or to a certain group of structures on that 

 species. Practically no real comparative study has been made of even 



