142 MEMOIRS ON THE COLEOPTERA 



more or less strongly reflexed at apex, having an approximately 

 trapezoidal form and is always strongly sculptured, with distinct 

 and strongly, medially sinuate suture; the elytra offer scarcely any 

 suggestion of the singular female modifications occurring in the 

 preceding genus. The material in my collection indicates two sub- 

 generic groups as follows: 



Antennal club curved and very much longer in the male than in the 

 female; elytra always completely immaculate. Colder sonoran 

 regions Group I 



Antennal club oval, small in size in both sexes; elytra generally maculate. 

 Neotropical regions Group II 



The tarsi are slender and filiform but differ greatly in length, not 

 only in the sexes but in different sections, especially of the first 

 group. 



Group I. 

 Subgenus Ochrosidia in sp. 



This is a large group of species, including glabrous and a few 

 sparsely pubescent forms. The color is very monotonously pale 

 brownish-flavate, with the head black or darker as a rule; they 

 occur in abundance throughout the nearctic and Sonoran regions 

 and, in fact, are the only members of the great tribe Cyclocephalini 

 inhabiting the Atlantic regions of North America; they are divisible 

 into two well marked sections of almost subgeneric weight as follows: 



Body stout in form; pronotum never margined at base; hind tarsi longer, 

 always longer than the tibiae even in the female; larger claw of the 

 anterior male tarsi long, only moderately arcuate, very unequally 

 cleft at tip, the outer ramus extremely slender and not extending 

 quite to the tip of the claw Section A 



Body more slender in form, elongate-oval; pronotum always margined at 

 base though incompletely as a rule; hind tarsi shorter in both sexes 

 and, in the female, very much shorter than the tibiae, sometimes not 

 as long as the tibiae in either sex; larger claw of the anterior male 

 tarsi very short, stout and strongly arcuate, the outer ramus ex- 

 tremely small, fine and at a long distance from the apex of the claw, 

 frequently broken away, leaving no apparent modification of the 

 upper edge Section B 



The first section includes all species of the well known immaculata 

 type, while the second is represented by longula Lee., and a few 

 allied forms, all confined to the Sonoran fauna, excepting marcida, 

 from Austin, Texas, and possibly seditiosa Lee., from the Mississippi 

 coast, which probably represent its extreme eastern range. 



