BY E. W. FERGUSON. 687 



the fundamental tuberculiform nature of the structure is trace- 

 able. 



The tubercles occur practically always in single series, almost 

 the only exception known to me, being a tendency in some 

 species of the sabulosustype towards reduplication in the 

 middle of the third interstice, this, however, being an individual 

 variation, and not constant in the species, or on both sides of 

 the same specimen. The third interstice is generally, and the 

 sixth almost invariably, continuously tuberculate; the second 

 and fourth always have fewer, and may have no, tubercles; while 

 the fifth is very variable, sometimes continuously tuberculate, in 

 other species only at the humeral angle. The seriate punctures 

 are smiU and shallow, often completely obscured, and almost 

 invariably nevejc foveiform ; the only exception being in the 

 aberrant convexus-group, where the punctures are large and 

 foveiform. One other point in the elytral sculpture may be 

 mentioned here, as I have made use of it in grouping the species; 

 that is the approximation, in some species, of the third elytral 

 interstices on the declivity; in these species, the second interstice 

 is crowded out on the declivity; in other cases, the second 

 interstice (though not necessarily the tubercles) is continued to 

 the apex. 



The ventral surface presents two forms of structure, in the 

 male, which I regard as of primary importance in the classifica- 

 tion of the genus. In the first section, the ventral segments are 

 more or less strongly maculate, with short subpubescence, near 

 the centre; and the apical segment, in the male, is channelled in 

 the middle, the channel being bordered, as a rule, on either side 

 by a small elevation. In the other section, the fifth segment is 

 not excavate, but there is a strong median ventral vitta of long 

 setose hair, extending from the metasternum to the apex of the 

 abdomen. The metasternum is short, but presents no special 

 features. 



The legs are moderately long; the anterior femora, in many 

 species, bear a narrow ridge along the outer half of the under- 

 surface. In the male of some species, the middle tibiae have a 

 strong subapical emargination; the posterior tibiae are similarly 



