1 -I Q [March, 



reallv only a few very short bristles on the peculiarly sculptured 

 siu-face, though, if we take oif one of the hind legs, we shall find that 

 the part concealed by it has a real minvite pubescence. There exists 

 in fact, a very great difPei'ence in this character between aquatlrus and 

 rugos'iis ; and in the Empleiiri, and the forms more or less related 

 thereto, I attach great importance to it. 



In the previous communication I have given an account of the 

 structure of the aedeagus, and I will conclude these remarks by some 

 observations of the bearing of this organ on the question of Helophorid 

 affinities. 



The aedeagus of the Heloijhoriyii is extremely similar to that of 

 the Hydrophilint ; indeed, if the structure l)e compared with that 

 of Anacaena or of Hydrnus, it will be found difficult to discover any 

 distinction of importance between them. 



Further, the structure is very homogeneous throughout the Helo- 

 nliorini ; there are, it is true, slight differences in the relation of the 

 lateral lobes to the median lobe that support the differentiation of 

 certain of the genera — Empleurus and Mecihelophorur. e.g. — but that is 

 the most that can be said. Again, in many of the closely allied species 

 the aedeagus appears to be quite similar, or at any rate so closely 

 similar that it is hard to believe that the structures offer any bar to 

 hybridisation. The difficulties that exist as to limiting some of the 

 species of Helophorini on account of the vai'iability of their slight 

 differential characters are well known to Coleopterists, and it is not 

 unreasonable to suggest that the variability may be due to 

 hvbridisation, as is now known to be the case in some genera of plants. 

 Many of the species of Hel'pJiiirini live in the most intimate 

 association, and this is not infrequently the case with the most closely 

 allied species; while copulation occurs apparently with great ease. 

 In short, I do not know any beetles in which hybridisation appears a 

 priori more probable than in the Helophorini. Whether it actually 

 occurs is a matter for future observation, as I am not aware of any 

 records of observations or experiments on this point. 



(To be continued.) 



