SCOTT—COLEOPTERA; HYDROPHILIDA, HISTERID A 229 
31. Bacanius mopinatus, Schmidt. 
Bacanius inopinatus Schmidt, Ann. Soe. ent. France, 1893, Bulletin, p. 102; Alluaud, 
Liste Coléopt., p. 110; Kolbe, Mitt. Zool. Mus. Berlin, v. 1910, p. 21. 
9 specimens, determined by comparison with a cotype kindly lent by Monsieur 
Alluaud. 
Wings: examined in | specimen, fully developed, twice as long as the elytron. 
Loc. Seychelles. Mahé: Cascade Estate, 800 feet or over, 1908—9; 1892 
(Alluaud). 
32. Bacanius atomarius, Sharp. 
Bacanius atomarius Sharp, Trans. R. Dublin Soc., iii, 1885, p. 128; Scott, Fauna 
Hawaiiensis, i. p. 510, Pl. 15, fig. 37, 1908. ; 
Two specimens from the Seychelles are smaller than the Hawaiian examples, but 
after close comparison of both upper and under surfaces, side by side under the microscope, 
I am unable to find any distinguishing characters. 
Loc. Seychelles. Mahé: Cascade Estate, 800 feet or over, 2 specimens. Hawaiian 
Islands (Oahu). 
Acritus, Leconte. 
Subgenus Haxicrirus Schmidt, Bull. Soc. ent. France, 1893, p. 103. 
This subgenus is distinguished from A/etes and Acritus s. str. by the mesosternum 
being produced forward into a blunt point, and by the anterior tibize being dilated, 
emarginate at the extremity, and furnished with short spines along their outer edge. In 
the specimens before me (Halacritus algarum) there is a small visible scutellum, as in 
Acritus s. str. Also the diverging striz on the metasternum become obsolete behind : 
they diverge rather widely, and then end blindly without curving at all: under a very 
high power there can be faintly seen a trace of a stria running down from the anterior 
corner of the metasternum to meet the diverging stria, but the two do not unite, and 
their course is such that, even if they did, they would form an angular or V-shaped stria, 
instead of the normal stria curving gradually round behind the middle coxa. Moreover, 
the striz on the 1st abdominal segment, although they curve normally, appear to become 
obsolete and not to reach the side edge of the segment. A somewhat analogous condition 
is seen in the Hawaiian Acritus (dletes) subrotundus (Fauna Hawaiiensis, iil. pp. 533—4, 
Pl. 15, fig. 33): in this, however, the striz on both metasternum and 1st abdominal 
seoment diverge very little and become obliterated behind after a very short course: this 
species belongs to a different subgenus and differs entirely from Halacritus in other ways. 
This character of the diverging striz in Halacritus appears not to have been noted by 
Schmidt. 
The nature of the wings is discussed below, under Halacritus algarum. 
33. Acritus (Halacritus) algarum, Schmidt (Plate 14, fig. 26). 
Acritus (Halacritus) algarum Schmidt, Ann. Soc. ent. France, 1893, Bulletin, 
p- 103; Alluaud, Liste Coléopt., p. 111; Kolbe, Mitt. Zool. Mus. Berlin, v. 1910, p. 22. 
SECOND SERIES—ZOOLOGY, VOL. XVI. 30 

