INTRODUCTION. S 



and easily defined that it oflPers no real difficulty. In the chiws 

 of the RuTELiN^, the outer one upon the fore feet and the inner 

 one upon the reiiiainiug feet (or, in other words, the posterior claws 

 of all the feet, if the latter are imagined as held at right angles to 

 the axis of the body) are always smaller than the rest and always 

 quite simple in form, while the longer one may he cleft at the 

 tip, lobed beneath, or distorted in shape. 



The existence of isolated and aberi-ant forms always renders 

 difficult the effort to find differential characters of universal appli- 

 cation to large aggregates of species, and where the real affinities 

 of such forms are uncertain it is better to separate them than to 

 force them arbitrarily into the great groups. Propomacrus (or 

 Eucliirus) and Desmonyx are peculiar Indian genera, having 

 relationships more or less indefinite with the Rutelin^, but 

 not according with any of the four great groups of Pleurostict 

 Lamellicornia as given in the Table on p. 23 of my previous 

 volume. I have treated each of these as belonging to a separate 

 subfamily. 



The following amplified Table will show the relationship of the 

 RuteliNjE to the other subfamilies of Pleurosticts occuri'ing in 

 the Indian region. 



Labrum membranous, not visible externally. 

 Mandibles not visible externally ; front coxae 



vertical Cetoniin^. 



Mandibles visible externally ; front coxse trans- 

 verse Dynastin^. 



Labrum thick, more or less exposed. 



Labrum (and maxillae) degenerate, scarcely chiti- 



nous Desmonychin^. 



liabrum well-developed. 



6th ventral segment not retractile. 



Claws unequal, separately movable, the 



shorter one always undivided Rutelin^. 



Claws equal (or if unequal, both cleft) 

 and not separately movable. 

 External lamelloe of the anteunal club 



enclosing the middle one Euchirin^. 



External lamella3 of the antennal club not 



enclosing the middle one Melolonthin^. 



6th ventral segment retractile Hopliin^. 



Structure. 



None of the Eutelin^e approach the size of the largest 

 DvNASTiNJE and Cetoniin^, few of them exceeding an inch in 

 length, and the external skeleton is generally less hard than in 

 these neighbouring subfamilies, from which results a rather 

 greater inconstancy of form. The remarkable outgrowths of 

 head and thorax seen in many of the Dynastin^ and a few 

 Cetoniin^ are not found in the present group, except in the 

 very singular Indian form Peperonota, the male of which has a 

 curious prolongation backwards of the thorax. But in several 

 genera nearly related to that there is an enormous enlargement 



B 2 



