Coleopterolugical Notices, VII. 353 



the Staphylinidse, a very extensive group, with structures varied 

 in almost every direction to an extraordinary degree, it has an 

 extremely fixed and constant form, while in the Omalini, the most 

 radical differences only serve for generic division, and, in extreme 

 cases of development such as Lesteva, they vary much from species 

 to species, in the two sexes, or even to some extent individually. 

 In the Pselaphidre, palpal structure is also of subordinate value, 

 as it may vary greatly within nearly all the tribes, but in the 

 Scydm8enid£e, the structure of this organ is of great importance 

 because of its constancy throughout groups of genera and species, 

 which it is evident, for other reasons, ought to be associated to- 

 gether. Any decided divergence in the palpal structure is held 

 in this revision to have tribal weight, and is always accompanied 

 by other important peculiarities of structure. 



Another character of vastly more importance in the present 

 family than in many other groups of the Coleoptera, and one 

 which has been singularly overlooked thus far, is the scutellum. 

 Even when very minute this sclerite displays an astonishing con- 

 stanc}"- throughout the various genera possessing it, and, in one 

 case, its complete absence forms an important tribal element. It 

 would be as remarkable an exception for any scydmsenid having 

 the fourth palpal joint subulate, the neck narrow and the eyes an- 

 terior in position, to present the slightest vestige of a scutellum, 

 as it would for a harpalid beetle to exhibit a claviform anten- 

 na. The scutellum has been made use of extensively in the 

 following memoir, and will be found to be a character of consid- 

 erable value. 



The Scydmaenidse form an extensive family, but the species are 

 so small in size as a rule, and live so concealed a life, that they 

 are seldom collected in numbers, and, with the exception of some 

 six or eight species, thej'^ appear besides to be either-individually 

 rare or local in habitat. That they ai-e very numerous in species, 

 is proved by the collecting of Mr. P. Jerome Schmitt about his 

 home in the mountains of Pennsylvania, where, in a single isolated 

 region, and that not one of the best, he has succeeded in bringing 

 to light about 37 distinct species, belonging to some 11 genera. 

 All of these were placed in my hands and have given a substan- 

 tial advance to our knowledge of these minute animals. 



The Scydmsenidpe are resolvably into two subfamilies by the 

 following: characters : — 



