INTRODUCTION. 10 



not found. Large males (Plate XIV, fig. 2) occurring tliere 

 have mandibles the curvature of which is uninterrupted 

 from base to tip and the teeth also form an uninterrupted 

 series, of which the largest is always the first, placed before 

 the middle instead of beyond it. Sujjposing these specimens 

 to indicate a distinct species, and unfortunately associating 

 with them a female of a very different species, Dr. Gravely 

 gave them the name of arrowi ; but a careful comparison of 

 females and small males from all districts has compelled me 

 to reject his view and to regard this also as a case of one species 

 with two male phases. 



A very abundant Stag-beetle, with a wide range in the 

 East, is Dorcus Htanus (Plate VII, figs. 1-4), a large black insect, 

 the males of which have the mandibles long and broad, except 

 at their curved tips, with the widest part toothed like the 

 edge of a saw. Again the large males exhibit two phases, 

 those from India and the Malaj^an region having very broad 

 mandibles (fig. 1), of which the toothed part occupies the 

 middle, Avhile in China and Jaj)an they are narrower and 

 relatively longer (fig. 3), with the toothed jiart of greater 

 extent. These two forms have been regarded as distinct 

 species, and the second named Dorcus jjlatymelus, but, since 

 the females (fig. 4) and small males (fig. 3) are alike ever\^vhere, 

 I regard them as local forms of a single species. 



The fact that this bifurcation is found in some of the com- 

 monest species, of which large numbers of specimens can be 

 brought together, seems rather significant. It leads to the 

 cjuestion whether other forms, at i)resent kno\A'Ti only from 

 a few specimens of each, may not be found to be similarly 

 connected when long series are available for comparison. 

 Many LucANiDiE are known only from single examples or 

 from specimens of only one sex. Even in common species 

 the phase of greatest development may be of relatively infre- 

 quent occurrence, the majorit}^ of specimens being of medium 

 size. It seems probable that the reason why certain remarkable 

 forms remain known by unique specimens only for long periods 

 is that they occur only at long intervals or under excep ional 

 conditions and perhaps for years together are actually non- 

 existent. 



A single specimen of a species of Onthophagus now in the 

 Calcutta Museum (0. lemniscatus) has a pair of extremely 

 long horns, hke twisted wire, upon the head, extending 

 backwards for a considerable distance and then bending 

 abruptly and reaching forward beyond the point of origin. 

 The specimen was taken in the Botanical Garden at Coonoor, 

 in Southern India. At my request, Mr. S. H. Butcher, a 

 botanist on the staff, made a prolonged search for further 

 specimens. He sent me numerous examples but every male 



c2 



