2 GEO. H. HORN, M. D. 



APHODIUS Illiger. 



At the time of my previous essay ou this genus it was supposed 

 that the fauna oi' our country had been nearly exhausted and that 

 but few new species remained to be discovered. Without any gen- 

 eral work the collectors in various parts of the country were unable 

 to separate their species, but it soon became evident that more atten- 

 tion was being given to the collection of the species by the aid given 

 by the synopsis, imperfect as it was. In less than ten years new 

 forms were sent me equalling in numbers those described by me as 

 new. The more conspicuous of these were described by Dr. LeConte 

 as already stated. 



In the synopsis of 1870 fifty-one species are given, one other was 

 accidentally omitted. Of these six are now considered synonyms. 

 The present essay enumerates eighty-two, nearly double the number. 

 Of these all are known to me in nature excepting cadaverinus and 

 guttatus, and seventy-eight are represented in my cabinet. Having 

 thus about as complete a series as usually falls to the lot of any one 

 it has been deemed expedient to review the whole material and 

 bring together fuller descrij)tions in one paper. As has been my 

 custom for some years the synonymy and bibliography have been 

 placed as a concluding poiiion and made complete so far as concerns 

 our fauna, the greater part of the synonymy of European species 

 being omitted. In these latter, besides the original citation, I have 

 added references to more modern and better descriptions, to which 

 the student is referred for fuller details of variations than I have 

 thought necessary to give. 



The great increase in the number of species has required some 

 modification of the arrangement made use of in my previous papers, 

 although I have endeavored to follow the lines proposed by Erichson 

 as far as our species would permit. It has seemed desirable to adopt 

 a course intermediate between that of Erichson and Mulsant, and 

 to recognize certain primary divisions to be called subgenera, with- 

 out, however, going to the extreme of the latter author. 



In our fauna four subgenera are recognized — Teuchestes, Colohop- 

 terus, Diajrierna and Aphodius (proper), the first two being repre- 

 sented by introduced Euroj^ean species ; the third is peculiar to our 

 fauna, and all have the large scutellum. Aphodius contains all the 

 species with small scutellum, and has been greatly subdivided, but 

 with our material we must either disregard the names proposed for 

 these divisions or nearly double the number at present existing. 



