1918.] F. H. Gravely: Passalidae of the World. 107 



The antennal lamellae normal .. .. .. L. gracilis, Heller. 1 



The first two antennal lamellae very short, the remaining four 

 exceptionally long . . . . . . . . L. ptoxoides, p. 105. 



The first two antennal lamellae very short, the remaining four 

 exceptionally long . . . . . . . , L. ytox, p. 105. 



The antennal lamellae normal . . . . . . . . . . 9. 



( The elytra separate ; insects of moderate size . . . . L. convpergus, p. 105. 



^. The elytra united ; insects of large size . . . . . . . . 10. 



( The outer tubercles much narrower than the space between 

 them, each being composed of two more or less distinct 

 blunt processes only ; the posterior intermediate areas 

 of the metasternum smooth . . . . . . L. moluccanus, p. 106. 



10< The outer tubercles at least as broad as the space between 

 them, each including an additional blunt process on the inner 

 side of, and some distance from, the two found in L. moluc- 

 censis ; the posterior intermediate areas of the metasternum 

 coarsely punctured . . . . . . . . L. gigas, p. 106. 



Genus PROTOMOCOELUS, Zang, 19056, p. 154. 

 =Pelops, Kaup, 1871, preoccupied. 

 Type, Passalus australis, Boisduval, 1835, pp. 246-247, pi. vi, fig. 21. 



Protomocoelus australis (Boisduval). 

 PI. I. 



Passalus australis, Boisduval, 1835, pp. 246-247, pi. vi, fig. 21. 

 Pelops australis, Kaup, 1871, p. 38. 



Five specimens from the Solomon Islands (including one from San Cristoval and one 

 from Bougainville), three from New Brittain, many from New Guinea (Milne Bay) 

 Stephansort and Isola Yule), and several from Waigeu, Aru (Wamma Dobbo and Ureiuning) 

 and Ceram. Also one specimen said to come from Australia. Length 30-47 mm. 

 The Solomon Islands specimens (except the one from Bougainville, which is only 35 mm. 

 long), and the specimen labelled Australia, are much the largest, none of the others exceeding 

 37 mm. in length. Apart from the Bougainville specimen the smallest of the Solomon 

 Islands specimens is 4 1 mm. long. I am unable, however, to find any constant structural 

 difference between the Solomon Islands specimens and the others, and am consequently 

 unable to recognize P. solomonis (Kaup) as distinct. P. australis is somewhat variable, 

 and the validity of Kuwert's species may be doubted. 2 



Protomocoelus australis is probably allied more closely to Labienus inaequalis than to any 

 other species yet described. It differs from it, however, in the structure of the mandibles (see 

 above, pp. 78 and 79) ; in the broader and often more widely separated, but very variable, 



1 See Gravely, 1913, for figures of this species. 



2 Passalus impressicollis, Boheman 1858, p. 40, cannot belong, as supposed by Kuwert, to the present genus, for its 

 outer tubercles are equal and obtuse instead of unequal and acute. It comes from Sydney, and not from Menado as stated 

 by Knwert ; it is said by Boheman to be allied to Mastochilus polyj^hyllus, and doubtless belongs to the same genus. 



p2 



