594 Mr, D, Sharp and Mi-. F. Muir on the Comparative 



the annular lateral lobes can, by it stretcbing, be brought into 

 the same plane as the axis of the aedeagus. 



The soldering together of the tips of the lateral lobes so as to form 

 a perfect ring, make this very different from Ancognatha. The two 

 forms have in common the unchitinised ventral plate of the basal- 

 piece. 



It should be noticed that in this form the consolidation 

 of the lateral lobes into a ring takes place in an indirect 

 manner. The apices of the lobes meet very nearly, but 

 not quite, and a distinct narrow space is perceived between 

 them ; but basally to this small space the ventral plate 

 penetrates between the lobes and is just there strongly 

 chitinised, though elsewhere it is quite membranous. 



This is a very interesting case. If we make use of a 

 teleological mode of expression we may say that it appears 

 that the tips of the lateral lobes are in process of becoming 

 consolidated so as to form a structure normal in Dynastinae 

 (compare with X gideon). The functional difference 

 between Ancognatha and Cyclocephala appears to be that 

 in the latter the orifice is held open permanently by the 

 ring-shaped lateral lobes ; while in the more Melolonthoid 

 structure of Ancognatha the lobes are mobile and the orifice 

 opens or closes as the situation requires. 



Cyclocephala would from this point of view appear to be 

 related to Xylotrnpes, while Ancognatha points to an affinity 

 with Dilohodems. 



Oryctes boas. 



The distal portion of the tambour is elongate and cylindrical, 

 the basal portion broad and short. The lateral lobes are long, 

 placed at a right angle with the cylinder, the orifice between 

 them viewed from behind is elongate and rather narrow. The 

 structure at the base of the median lobe is rather perfect ; the 

 chitinisation of its anterior-jpart on one aspect is met by a V-shaped 

 prolongation from the other aspect, and by the conjunction of the 

 two a complete ring-encasement is formed. We have already stated 

 that we have not been able to decide as to the nature of this 

 chitinisation. 



Dilohoderus dbdems. 



The aedeagus is here short, broad at the base, and gently 

 narrowed to the tip so as to be somewhat conical in form viewed 

 dorsally. The lateral lobes are articulated so as to admit of a 



