194 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



common. However, the union of two or more of these groups pro- 

 duces an assemblage that cannot be adequately characterized to per- 

 mit ready separation from the other genera included in section III of 

 the diagram on page 191. 



This attempt to reduce the genus Ludius to definable limits is 

 merely suggestive. The larval record is too incomplete to provide 

 the necessary perspective, but it might supplement the evidence from 

 adult studies. There are two alternatives to the suggested subdivi- 

 sions given above: make every "species group" a new genus, or 

 leave the genus in its present indefinable state. From the purely 

 phylogenetic viewpoint, it is doubtful if genera are completely de- 

 finable. Therefore group limits for taxonomic purposes are very 

 difficult to draw. 



Species seem to be well defined in those parts of the genus that 

 Brown has revised. His species have been substantiated wherever 

 adequate larval material was available for study. However, very 

 detailed examination frequently was necessary to discover the sepa- 

 rating characters of closely allied forms. Brown's species concept 

 appears to be valid, but any narrower concept could not be supported 

 by larval evidence. As more material becomes available, it is quite 

 possible that larval characters will not be found to separate all species 

 that Brown has recognized. Such a result can be expected, since 

 distinctions that are evident in the definitive adults might be ob- 

 scured in the developmental stages. 



Ludius rotundicollis (Say), as currently recognized, appears to in- 

 clude more than one species. The larvae from the eastern States 

 and those from the western States are morphologically distinct and. 

 therefore, should be considered as distinct species. 



The Athous Complex 



In contrast to the genus Ludius — which has been allowed to de- 

 velop into an indefinable assemblage — other parts of the Lepturoidini 

 have been separated into smaller, closely related genera. Thus 

 Elathous, Hemicrepidius, and Lcptiiroides are very closely allied to 

 the genus Athous as recognized at present, but Athous itself is poly- 

 morphic. As illustrated on page 191, sections HI and IV, Athous 

 consists of two main parts which are less closely related to each 

 other than to other established genera. The failure of European 

 workers to recognize the genus Hemicrepidius in their fauna is due 

 to its"* similarity to Athous. The European Athous niger (Linnaeus) 

 and its allies are typically Hemicrepidius. Whether Hemicrepidius 



