60 PROCEEDINGS OF THE NATIONAL MUSEUM vol.89 



ber of species that by the strongly pectinate tarsal claws and prom- 

 inent transverse carina of the vertex appear to form well-marked 

 groups, but when an attempt is made to separate these groups gener- 

 ically or even subgenerically on good characters the hopelessness of 

 the task is at once apparent. In certain species, whose males have 

 the tarsal claws strongly pectinate or serrate, the claws of the female 

 are toothed and have hardly visible serrations, and such females are 

 separable from Phyllophaga only by possessing a frontal carina. On 

 the other hand, such species as Listrochelus cavata Bates, L. meadei 

 Saylor, L. cochisa Saylor, and L. micros Bates do not have any trace 

 of the transverse frontal carina, nor do they have even the posterior 

 area of the front marked by a transverse boundary of rugose punctures 

 (as in L. timida Horn and L. senex Horn)^ but they do have (at least in 

 the male and much less noticeably so in the female) strongly pectinate 

 or serrate tarsal claws, so that their inclusion in the Listrochelus 

 group of species is necessary. The only alternatives (other than 

 suppressing Listrochelus entirely) are to erect half a dozen or more 

 purely artificial genera or else to reduce the name Listrochelus to a sub- 

 genus of Phyllophaga (into which it grades gradually and completely 

 through such species as L. cavata and allies, L. senex, L. timida, and 

 others to a lesser extent), and I feel that the latter course is justified 

 and necessary. Admittedly, by preserving Listrochelus as a valid 

 name at all we are maintaining a somewhat poorly defined unit of 

 Phyllophaga (since the two must be separated by a combination of 

 characters any one of which may fail), but since by so doing proper 

 identification of the included species is facilitated, certain purposes of 

 taxonomic research are better served. 



In a recent revision of the United States Phy talus (1939) the author 

 found it necessary to reduce that group to subgeneric standing under 

 Phyllophaga. In this connection the two genera Chirodines Bates and 

 Chlaenobia Blanchard may be mentioned: the former is separated 

 from Phytalus only through having the tarsal claws of the anterior 

 and middle legs of the male (female unknown) simple. This is 

 obviously a poor character upon which to separate genera, as we have 

 many instances in other genera and subgenera where the teeth on the 

 claws vary widely within the group (e. g., Anoplosiagum, Listrochelus). 

 Until the female is found and is proved also to possess simple anterior 

 tarsal claws as does the male, I prefer to regard Chirodines as at most 

 a subgenus of Phyllophaga. 



The genus Chlaenobia, ably revised by Chapin in 1935, is separated 

 from Phytalus only tlu-ough having the "male tarsal segments thick- 

 ened and densely pilose below"; Phytalus chlaenobiana Saylor is 

 practically inseparable externalh^ from the male Chlaenobia tumulosa 

 Bates both by general facies and characters, if the pilose and broad- 



