692 REVISION OF THE AMYCTERIDES, iv., 



what features can be regarded as of specific value; but the 

 species, as a whole, fall into fairly definite groups. 



Macleay, in his second paper, divided the genus into four 

 Sections, depending upon the characters of the elytral interstices, 

 in particular upon the fifth or humeral, termed by Macleay the 

 fourth. At first sight, this would appear a satisfactory method, 

 the genus being subdivided into the following groups : 



1. Fourth interstice of the elytra closely and continuously 

 tuberculated. 



2. Fourth interstice not tuberculated, or only close to the 

 shoulder. 



3. Fourth interstice remotely tuberculated or slightly elevated. 



4. Interstices of the elytra somewhat costate. 



A closer examination of the species arranged by Macleay 

 under these groups revealed the existence of several anomalies, 

 and it seemed to me that some underlying primary factor had 

 been overlooked. Such a factor, I think T have discovered in 

 the characters of the v^entral surface (in the male), two main 

 types of structure existing in the genus. Asa rule, it is not 

 desirable to form primary divisions on sexual characters, but 

 this seems unavoidable in the Amycterides. I would, therefore, 

 divide the genus into two primary sections. 



Section i. — Median ventral segments at most maculate, never 

 vittate; fifth segment longitudinally channelled in the g. 



Section ii. — Ventral surface with a strong, median, longitudinal 

 vitta, fifth segment not channelled in the (J. 



The first Section comprises Group i., which may be conveni- 

 ently termed the Adelaidce-gvouip, and it contains the type of the 

 f^enus. The number of species belonging to the Section is com- 

 paratively small, so that I have not considered it necessary to 

 subdivide them into groups, though they exhibit variation in 

 characters utilised for further subdividing Section ii. 



The second Section comprises the bulk of the species, and, for 

 convenience, may be subdivided into four groups. The relations 

 of the groups may be conveniently stated as follows : — 



