COLEOPTERA OF BAJA CALIFORNIA. 395 



The differences between this species and -ftoralis are 

 almost generic and are as follows : 



Sides of clypens i^arallel; iipper tooth of anterior tibia small; anterior 

 claws simply cleft. fioralh. 



Sides of clypeus convergent; upper tooth of anterior tibia well developed; 

 anterior tarsal claws dissimilar, the anterior one with a lobe-like tooth 

 at base, both claws cleft at tip. convergens. 



It is probable that all the specimens seen are males, as 

 none of them have any anterior tibial spur and the pyg- 

 idium is nearly vertical. 



As classifications now stand, Oncerus is fairly well 

 placed in the Chasmatopterides as defined by Lacordaire, 

 but the same group as constituted in our fauna (Classifi- 

 cation, p. 249) is not a natural one. Podolasia and Acoma 

 should be separated by their simple claws. 



Chnaunanthus has a distinct labrum concealed beneath 

 the clypeus, while Oncerus has the labrum connate with 

 clypeus, as in Phyllotocus and Cratoscelis more especially, 

 as well as in Serica. 



There seems to be a great need at the present time of 

 a revision of the relationships of many genera at present 

 placed vaguely among the Melolonthid^. 



Mr. H. W. Bates remarks (Biol., vol. 2, pt. 2, p. 129), 

 in describing Aporolaus: "An interesting generic form 

 * * * demonstrating that the mouth-structure (espec- 

 ially the free bilobed ligula) is more to be relied upon 

 than the position of the abdominal spiracles as indications 

 of natural affinity in this portion of the Lamellicorn series." 



In emitting this opinion Mr. Bates seems to have been 

 influenced by a reverence for the classification then ex- 

 isting. From my own studies, made necessary by my 

 defense of the position of Pleocoma and by a critical ex- 

 amination of very many obscure genera of Lamellicorns, 

 it seems clear that the free bilobed ligula and laparostict 

 spiracles are concurrent characters. 



