1853.] ^^ 275 



which have an appearance of being truly natural, that 1 ha^6t considered it 

 prudent to adopt their views. ^^'rv^rrifSr?^*^ ' 



Among some of these groups, (e. g. S. lapponica, S. americana and S. ramosa,) 

 appear several forms, which are undeniably distinct in their origin and distribu- 

 tion and yet do not present characters sufficiently definite for their perfect 

 separation. Many genera among more highly organized animals presenting 

 this same peculiar specific relation will occur to the mind of every naturalist, 

 but this is, I believe, the first example distinctly noticed among Articulata ; 

 nor can 1 find in scientific memoirs any allusion to a doctrine, which flows very 

 naturally from such observations, viz : There are in nature genera so constituted 

 that their division can naturally be made only so as to exhibit assemblages of 

 individuals, which are multiple and distinct in their origin, but which are so 

 closely related that any attempt to define and isolate them must result in con- 

 fusion. The interpretation of so called geographical varieties, is obviously a 

 portion of this doctrine ; but for the present, I must merely content myself with 

 this brief notice of a view, which, whether it be eventually proved correct or 

 erroneous, might ere this have exerted a beneficial influence upon certain por- 

 tions of Natural History, where The zeal for creating irrecognisable species has 

 been pushed to a prodigious extent. 



Div. 1. Silphales genuini. 

 Trochanteres postici fulcrantes ; coxas posticce approximate * 



Necrophorus Fabr, 



A. Thorace convexo, tenuiter marginato, antice non impresso. 



1. N. m e d i a t u s , niger, thorace obovato, antice dense punctulato, lateribus 

 et basi punctato, elytris macula humerali, altera transversa ante medium, 

 tertiaque lunata versus apicem rubris ; antennarum clava ferruginea ; pectore 

 abdonninisque basi ad latera auropilosis. Long. '87 -95. 



Fabricius, Syst. El. 1, 334 : Latreille, Gen- Ins. 2, 5. 



Southern States, Missouri Territory and Texas. This very distinct species 

 diff'ers from all the succeeding ones by the epipleurae being narrower, less in- 

 flexed, and less distinctly margined above. The posterior tibiae are very much 

 dilated at their extremity. In the male, the anterior tarsi are only moderately 

 dilated, and the yellow hair at the base of the abdomen is more abundant. In 

 both sexes the rhinarium is triangular. 



Among the specimens from Nebraska are varieties in which the anterior 

 transverse spot is divided; in some the outer part of this divided spot is efiaced ; 

 in such individuals the posterior lunate spot is much reduced in size. 



B. Thorace antice transversim impresso, margine laterali anguste depress. 



2. N. marginatus, niger, thorace obovato, marginibus parce punctulatis, 

 lateribus vix sinuatis, elytris lateribus, fascia communi ante medium, alteraque 

 utrinque subapicali rubris ; antennarum clava ferruginea ; pectore aurapiloso. 

 Long. -57 88. 



Fabricius, Syst. El. 1, 334. 



New York, Georgia, Texas, Nebraska and California. The rhinarium is red 

 and triangular ; the posterior fascia does not entirely reach the suture, and its 

 outer portion is contiguous to the apical margin. The anterior band is some- 

 times interrupted towards the side, and sometimes one of its posterior dentations 

 is prolonged so as to reach the inner part of the posterior band. The anus and 

 margins of the abdominal segments are ciliate with black hairs. The anterior 

 tarsi of the male are moderately dilated. 



3. N. Melsheime ri, niger, thorace obovato, lateribus subsinuatis marginibus 

 punctatis, epipleuris elytrorumque faciis utrinque duabus dentatis rubris ; anten- 

 narum clava ferruginea, basi nigra, pectore anoque flavo-pilosis. Long. '92. 



* This last is a character found in the whole group ; it is merely added here 

 for the convenience of those who may desire to consider Scydmaenidae as a 

 division of this, and not a distinct family. 



