34 LUCANID^ AND PASSALID^. 



of classification which is applicable only to one sex and only 

 to large specimens of that sex. In a lireliminary note dealing 

 with the genera of Lucanid.e publislied in 1935 (' A contribu- 

 tion to the classification of the Coleopterous family Lucanid.e,' 

 (Trans. R. Ent. Soc, vol. Ixxxiii), I therefore proposed the 

 abandonment of all those genera based upon features found 

 in one sex only. The result of applymg this not unreason- 

 able prmciple to the Indian fauna has been the reduction 

 of the number of genera containing the 133 Indian species 

 from 30 to 15. 



It can be admitted that there are certain groups of animals 

 in wlxich it is necessar}' to base genera, and even superior 

 divisions, upon the characters of one sex only (e. g. when the 

 other sex has degenerated to a condition in which many of 

 the important organs have disajjpeared) . Female Lucanid^^ 

 show no degeneration, all their organs are extremely well- 

 developed and the species are well differentiated. Within 

 the limits of the family, important grouji characters are found 

 in both sexes and the close similarity between many of the 

 females undoubtedly indicates a close relationship which it 

 is not i^ermissible to overlook. 



It camiot be argued that the amalgamation of various 

 so-called genera, the females of wliich are destitute of any 

 important structural differences, is undesirable on account 

 of the large number of component sj^ecies in the resulting 

 genera, for the entire family contains fewer species than such 

 a genus as Onthophagus, an attempt to subdivide which by 

 means of its male characters would result in hopeless confusion. 

 The laiowii species of that genus undoubtedly form a much 

 smaller proportion of those actually existing than the known 

 Lucanid^ bear to the jjrobable total membership) of the group. 



It may i)erhaps be thought that, unless both sexes are 

 present, it may be difficult to judge whether a particular 

 feature is peculiar to one sex or not but, since in general 

 the characteristics of the male consist in an exaggerated 

 proportional development of certain parts of the body and 

 since the degree of development will generally be found to 

 b5 inconstant whenever more than one specimen is present, 

 tills difficulty is actually not a very serious one. Greater 

 difficulty may be experienced when it is desired to correctly 

 associate the two sexes of a species. So great are often the 

 differences that it may be almost impossible to find any 

 identical features common to both. The repeated occurrence 

 of the two sexes in the same localities may liave to be awaited 

 before their specific identity can be assumed. In the absence 

 of characters in common, I have found it necessary to draw up 

 keys for each sex separately, except in the case of genera with 

 little or no dimorphism. 



