DR. F. LEUTHNER ON THE ODONTOLABINI. 395 



arrived at very interesting results, which I will reserve for future publication, as they 

 are rather beyond the limits of the present investigation. 



The table opposite will show how difficult it is to decide such questions with 

 insufficient material, how differently various authors have attempted to do so at 

 different times, and how different species have been alternately separated and united 

 from the time of Hope and Burmeister to the present day. 



(4) Odontolabis alces, Fabr. {a morphological sticdy). 



Among the above-mentioned species Odontolabis alces deserves special study, as it 

 is extremely interesting both from a historical and from a morphological point of 

 view ; and on account of the great mass of material at my disposal, which enabled me 

 to study it more fully than any other species. 



(a) Evidence of the Specific Identity ofO. dux, Westw., O. alces, Fabr., and 



O. cumingi, Hope. 



Through the kindness of Herr G. Schneider, of Basel, I have been enabled to 

 examine 223 specimens of this Stag-Beetle, which is generally known as 0. dux, Westw. 

 They were received from Manilla, and 112 specimens were males and 111 females. 

 The females varied in length from 39-52 millim., and the males from 45-99 millim., 

 inclusive of the mandibles. 



When I first examined the whole series, I was immediately struck with the great 

 similarity of the females (PI. LXXXIX. fig. 8), while the males appeared in four 

 distinct forms (PI. LXXXIX. figs. 1, 3, 5, 6), which nevertheless all seemed to belong 

 to the same species, as they were connected together by transitional forms. This cir- 

 cumstance, and the large amount of material before me, naturally led me to make 

 further investigations, as I had long been anxious to meet with such a series, in order 

 to study the laws and limits of variability between individuals belonging to one and the 

 same species. In this case no doubt could exist respecting the correct identification of 

 the sexes, as they were all fi'om the same locality. 



It was only necessary, in the first instance, to ascertain whether the females all 

 belonged to the same species. If so, there could be no doubt that the males would prove 

 to do so also. But I went another way to work, and verified this point at a later time, 

 when I had learned to distinguish between the females of a considerable number of 

 species of Lucanidse, which, owing to their great resemblance, is a most difficult task. 



I also convinced myself by careful examination that the smallest males (PI. LXXXIX. 

 fig. 7), although so similar to the females, possessed fully developed sexual organs, 

 and were not to be regarded as sexually imperfect individuals, as some authors have 

 suggested. By a careful selection I was enabled to pick out an almost uninterrupted 



series of transitional forms from the largest to the smallest males. 



3n2 



