280 Mr. J. Nietner on new Ceylon Coleoptera, 



unable to express the characteristics of the insects from which it 

 is drawn in more precise terms, although they have features quite 

 peculiar to themselves, by which they are easily recognized when 

 once seen. 



The points in which the three species which form this genus 

 more or less disagree are the following : — (I) The labrum : this 

 is more transverse in H, elegans, and less deeply emarginated in 

 H. ruficollis than in the other two species respectively ; still in 

 all three it is emarginated^ and has, moreover, the peculiarity 

 of being furnished with bristles at the two anterior corners. 

 (2) The mentum : this is subquadrately emarginated, the lobes 

 being strongly rounded on the outer side, and abruptly acumi- 

 nated at the apex ; at the base of the emargination it is furnished 

 with a broad, excavated tooth, which is inflected and obtuse at 

 the apex : so far all three species agree ; however, whilst in H. 

 elegans and ruficollis this tooth is slightly emarginated at the 

 apex, it is sharply notched in H. bimaculata, in fact, bilobed, the 

 lobes being large and rounded at the apex. I look upon this 

 notch, which is sharp, but not deep, as a mere variation from the 

 emargination existing at the apex of the tooth of the former two 

 species. (3) The palpi : these, the labial as well as maxillary, have 

 their terminal joint truncated at the apex ; and so far, again, all 

 three species agree : however, whilst this joint is of elliptic form 

 in the palpi of H. ruficollis, it is in H. elegans only so in the labial 

 ones, that of the maxillary ones being cylindric at the base. In 

 H, bimaculata, finally, this joint is rather club-shaped or sub- 

 triangular, and more strongly truncated than in the former two 

 species. (4) The ligula : this organ is of subcoriaceous texture, 

 middling size, the shape of an oblong square, free, and trans- 

 versely truncated at the apex ; these characters are common to 

 all three species, and in H. ruficollis I have nothing to add to 

 it ; however, the anterior margin, which is straight in this spe- 

 cies, is slightly bisinuated in H. elegans, the outer angles being 

 acute, and the central one obtuse. The ligula of H. bimaculata 

 differs from both the former in as far as it is narrowed towards 

 the apex and depressed towards the sides and the front; the 

 anterior margin is otherwise cut away straight, without any 

 sinuosities, but it is rather strongly armed with bristles. The 

 paraglossse agree in all three species, in as far as they are highly 

 developed, reach much beyond the anterior margin of the ligula, 

 and are more or less bent inwards. Their greatest development 

 they assume in H. elegans, in which they nearly touch each 

 other in front of the anterior margin, being cylindric and slender 

 at the same time. In H. ruficollis the paraglossa) are somewhat 

 shorter and straighter, and in H. bimaculata still more so. 



In all other points the three species perfectly agree, in saying 



