PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



by the 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol. 84 Washington: 1936 No. 300! 



REVISION OF THE NORTH AMERICAN BEETLES OF 

 THE STAPHYLINID SUBFA]\nLY TACHYPORINAE— 

 PART 1: GENUS TACHYPORUS GRAVENHORST 



By RicHAKD E. Blackwelder 



Walter Rathhone Bacon Scholar, Bmithsonian Institution 



Only once have the American species of beetles of the genus 

 TachypoTus been monographed, and nearly 60 years have passed 

 since that time. Only one new species has been described and little 

 added to the knowledge of the genus since Horn's revision in 1877.^ 

 The members of this genus have always been considered difficult to 

 differentiate because of their feeble characters. Horn states that 

 they "resemble each other so closely that it is only with difficulty 

 that they can be described, so that their feeble differences may be 

 made apparent." This is to some extent due to the fact that color 

 has been used almost exclusivel}^ for distinguishing the species, in 

 spite of the recognized fact that this character is frequently very 

 variable. Certain species are distinct and may be readily separated 

 by the color pattern, but with others great confusion has been brought 

 about by the attempts to separate the species in this way. 



Even the structural characters available are few and rather feeble. 

 An attempt to utilize the genitalia of both the male and female has 

 led me to the conclusion that the very slight and inconstant differ- 



^ Horn, George H., Synopsis of the genera and species of the staphylinide tribe Tachy- 

 porini of the United States. Trans. Amer. Ent. Soe., vol. 6, pp. 81-128. pi. 1, 1877. 



82751—36 39 



