4 



1918.] F. H. Gravely : Passalidae of the World. 103 



The above-mentioned species of Mastocliilus may be grouped into four sub-genera as 

 indicated above (pp. 97-98), and may be distinguished from one another thus : — 



I. Sub-genus PHAROCHILUS, Kaup. 

 The median part of the rnentum with at most two or three 



punctures . . . . . . . . . . . . . . 2. 



The median part of the mentum strongly punctured through- 

 (^ out . . . . . . . . . . M . pu nötiger, p. 99. 



( The lateral lobes of the mentum with a more or less narrow 



matt border on the outer side . . . . . . . . . . 3. 



2-N 



The lateral lobes of the mentum broadly matt on the outer 



side . . . . . . . . M . politics, p. 99. 



The ridges of the elytra obsolete in the extreme posterior angles M. dilatatus, p. 98. 



The ridges of the elytra normal . . . . . . M. nitidulus, p. 98. 



II. Sub-genus MASTOCHILUS, s. str. 

 The frontal area small, almost equilaterally triangular, raised 



above the general surface of the head . . . . M. quaestionis, p. 100. 



The frontal area not raised above the general surface of the head, 

 usually much broader than long . . . . . . . . . . 2. 



r The secondary scars very variable in development ; when 

 present always extending inwards from the ends of the 

 anterior margin of the median part of the mentum . . M . australasicus, p. 100. 



The secondary scars always developed as a pair of fine grooves 

 defining a small and more or less equilaterally triangular 

 shield in the middle of the anterior margin . . . . M. polyphyllns, p. 100. 



III. Sub-genus ANALACHES, Kuwert. 

 The lateral grooves of the elytra much broader than the ridges 



between them ; the transverse ridges between their enlarged 



matt punctures more or less obsolete . . . . M. austraUensis, p. 101. 



The lateral grooves of the elytra narrow and strongly punc- 

 tured . . . . . . . . . . M . puberilis, p. 101 . 



IV. Sub-genus CETEJUS, Kaup. 



The left outer tubercle pointed, directed forwards or a little 



outwards . . . . . . . . . . . . . . 2. 



The left outer tubercle truncate, directed inwards . . . . M . peltostictus, p. 102. 



The secondary scars on the mentum represented by a more or 



less broken transverse groove a little behind the anterior 



margin . . . . . . . . . . M. grabowskii, p. 102. 



The groove formed by the secondary scars on the mentum deep 



and unbroken . . . . . . . . M. sodalis, p. 102. 



Genus LABIENUS, Kaup, 187 1, p. 39. 



Inch Aurelius, Kuwert, 1896 ; Hyperplesthenus, Kuwert, 1898 ; Kawpioloides, Gravely, 

 1913 ; Kaupiolus, Zang, 19036 (=Vellejus, Kaup, 1871, preoccupied). 



Type, Eriocnemis ptox, Kaup, 1868a, p. 25. 



