178 GEO. H. HORN, M. D. 



to his solicitation, and found the work far greater than he anticipated. 

 In fact, beyond the convenient arrangement of the material I was com- 

 pelled to begin the work entirely anew, and the results of my study are 

 here given, with the hope that something more useful is presented than 

 mere descriptions of new species. 



PHIL,OXTHUS Curtis. 



In this genus, as at present restricted, the terminal point of the max- 

 illary palpi is slender and acicular, longer than the third joint. The pos- 

 terior tarsi have the first and fifth joints either equal, or with the first 

 a little longer, the intermediate joints short, and together rarely longer 

 than the first joint. 



With Philonthus I have united those species, referred by Fauvel, to 

 Hesperus, as I am unable to see that the metasternum in them differs in 

 any marked degree from very many other species. 



After separating €afius and Actobius, the genus Philonthus remains 

 very largely represented by species in nearly every part of the world ; 

 some are cosmopolitan in their distribution. In order ts facilitate the 

 recognition of the species it is necessary to sub-divide the mass by some 

 characters sufficiently constant. After a careful study I have adopted a 

 modification of the method proposed by Erichson, based on the dorsal 

 punctures of the thorax. The change proposed consists in the separation 

 of those species in which the anterior tarsi of the male are slender and 

 not dilated from those with the same tarsi more or less dilated in both 

 sexes. It may be said, in objection to this method, that the female tarsi 

 are more slender than in the male, and consequently with the former sex 

 only at hand there will be difficulty in placing them in the proper series. 

 In our large series I have never observed any such difficulty. When the 

 front tarsi of the male are undilated they are slender, filiform and rather 

 spinous beneath, the females not diff"erent. In the other series, however, 

 the tarsi, no matter how narrow the dilatation, are never filiform, and the 

 under side is finely silken pubescent in both sexes. 



The dorsal punctures come next in value as a means of further sub- 

 division, — first, those with a regular dorsal series of three, four, or five 

 punctures, and second, those with the punctures very irregularly placed, 

 not in series, and sometimes quite dense. 



In the numeration of the punctures the method adopted by Fauvel 

 has been followed, that is, only those punctures are counted which are 

 strictly discal in their position, thus aeneus is a tripunctate species, but 

 by the Erichson notation is said to have four punctures. The latter 



