32 INIr. D. Sharp's Cuntrihiitions to the 



iiiontlonlng a fi^enns to -winch he sujiposcs it to belong ; and 

 thus it happens that when dealin<>; with such an enormous 

 mass of species as exist in the Insecta, the veiy greatest 

 confusion arises. We are not only practically at extreme 

 variance "vvith our predecessors as to what constitutes a 

 genus, but the very greatest discrepancies of opinion 

 prevail among presently active students on this point. 

 I shoidd therefore have preferred in this paper never to 

 have used the word genus at all, and not to have con- 

 cerned myself with the question of genera, for I am quite 

 convinced that when dealing Avitli a limited geographical 

 fauna the student is not in a position to decide as to 

 questions of genera ; and this, I hold, would still be the 

 case, even if an agreement as to what constitutes a genus 

 prevailed among naturalists. The system at present in 

 vogue, however, has not allowed me to do this ; and in 

 accordance with the usual custom of naturalists I have 

 had to constantly use the Avord genus, and to make use of 

 the generic system as the basis of my dealing with species. 

 I have therefore adopted the plan of making as few new 

 generic names as possible. Some farther observations on 

 this point will be found among the remarks prefixed to 

 the descriptions of the species of Sunius in this paper. 



In examining these insects for description I have paid 

 a good deal of attention to the sexual characters, and have 

 ascertained in a great number of species not only what are 

 the secondary sexual characters of the males, but also 

 what is the actual structure of the rcdeagus. It has long- 

 been known that the secondary male characters afford 

 a most valuable aid to the distinction of the species of 

 insects of various orders, and it has also been ascertained 

 in several groups of Coleoptera that the redeagus itself 

 exhibits very remarkal)le differences of structure even 

 in the case of closely allied species. After making an 

 examination of the {edea<i"us in a large number of the 

 species here described, I am led to think that the in- 

 vestigation of the structure and variations of this organ 

 in the Coleoptera (and no doubt in other insects), would 

 lead to highly important biological conclusions. I am 

 able to state that in one group of the StaplnjUnhUp, viz., 

 the Piestini, the jodeagus is excessively small, and varies 

 but little from species to species; while in other groujis it 

 beconies a large comfjlex structure, varying greatly from 

 species to species. This is the case in many Pa'dcrini, 

 Ahocharhii and Puiophilini, The variations of this 



