32 Mr. D. Sharp's Contributions to the 



mentioning a genus to wlilcli he supposes it to belong ; and 

 thus it liapi)cns tliat when dealing with such an enormous 

 mass of sj)ccics as exist in the Insccta, the very greatest 

 confusion arises. We are not only ])ractically at extreme 

 variance Avith oiu* predecessors as to what constitutes a 

 genus, but the very greatest discrepancies of opinion 

 prevail among ])resently active students on this point. 

 I should 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 Avith 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 Avhat 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 Avith species. 

 I have therefore adopted the plan of making as few new 

 generic names as possible. Some farther observations on 

 this point Avill be found among the remarks ]n-efixed to 

 the descriptions of the species of Sunliis in this ])aper. 



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 Avhat are 

 the secondary sexual characters of the males, but also 

 what is the actual structure of the a^deaijus. It has lon<]^ 

 been knoAvn that the secondary male characters afford 

 a most A'aluable aid to the distinction of the species of 

 insects of various orders, and it has also been ascertained 

 in several groups of Coleoftera that the JEdeagus itself 

 exhibits very remarkable differences of structure CA'en 

 in the case of closely allied species. After making an 

 examination of the aideagus in a large number of the 

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

 vestifjation of the structure and variations of this organ 

 in the Colcoptera (and no doubt in other insects), Avoidd 

 lead to highly important biological conclusions. I am 

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

 the Plestini, the redeagus is excessively small, and A'aries 

 but little from species to species; A\'hile in other groups it 

 becomes a large complex structure, A^arying greatly from 

 species to species. This is the case in many Pccdrrini, 

 Aleochai'ini and Phiophilini. The variations of this 



