22 INTEODUCTION. 



many authors (few of them laying claim to any comprehensiveness 

 or continuity), which form a large part of the literature of this 

 subject. 



Por the purpose of accurate identification it is obviously 

 desirable that every group should be distinguished by features of 

 both sexes, but unfortunately in the Lamellicornia, in which, more 

 than in any other beetles, the most salient features are seen in 

 the male alone, this principle has been Aery frequently infringed. 

 Species and genera have been constantly based upon examples of 

 one sex only and often without ascertaining or recording the sex. 

 Sexual characters may be the chief criteria in the discrimination of 

 species, and it may even be necessary to separate forms of which 

 one sex appears to us to be without differential characters, but I 

 consider such features, unconfirmed by any other, quite inadequate 

 for forming genei'a or superior divisions. They may be \aluable 

 as supplementing more fundamental, but less obvious differences, 

 but as a rule they are very inconstant, and species whose relation- 

 ship is undeniably very close often display wide differences in this 

 respect. Genera which have been sunk on this ground will often 

 be found to contain very few, or only one, species. 



Wherever any marked external difference between the two sexes 

 is found it has been pointed out, and care has been taken to exclude 

 from the general descriptions all features distinctive of one sex. 

 As it sometimes happens that a species is known only from a 

 single specimen, or examples of one sex, it is not always possible to 

 distinguish such features. 



In order to ensure accurate nomenclature, no effort has been 

 spared to obtain actual types or co-types for examination whenever 

 possible. Unfortunately some have not been traced, but mention 

 of the present location of the type has been made m lien it has 

 been ascertained, and those studied in the course of this work are 

 indicated with an asterisk. 



It should perhaps be mentioned that all descriptions are drawn 

 from Museum specimens and, as regards colours at least, will 

 perhaps be found not always to apply accurately to living speci- 

 mens, owing to inevitable changes which take place after death. 

 Such knowledge as the author has of the insects in their natural 

 state is derived from European forms alone, a disadvantage which 

 is to be regretted, although it must be remembered that in so vast 

 a region as India only a fraction of the species of any large group 

 are likely to come under the observation of any single individual 

 even with the maximum of opportunity, whilst it is in Europe 

 alone that that fauna can be studied with even approximate com- 

 pleteness and in relation to the faunas of adjacent regions and of 

 the world in general. 



The Lamellicornia are divided into three Families which may 

 be briefly distinguished as follows : — 

 Antenna? not elbowed nor capable of being 



rolled up, the joints of the club very thin 



and doselv co-adapted SCARAB.flEIDiE. 



