On Aquatic Carnivorous Coleoptera or Dytiscida. 703 
tinct species, the undersurface being of a pure yellow colour, and the yellow cinc- 
ture of the upper surface being even broader than in that specis. 
Australia, (Darling River). 1120. 
Il. 77.—Genus HOMGIODYTES. 
Coxal lines absent ; unguicular cleft broad and rounded at base. 
This genus comprises three species* found in Australia and New Zealand. They 
form two well-marked groups :— 
Prosternum distinctly channelled along the middle, postero-external 
5 : 2 No. 110. 
angle of hind femur rectangular; size small (15 m.m.) long. 
Prosternum indistinctly grooved ; paste SestoanAL angle of hind Nos. 1101 and 1109. 
femur acute or spinose ; size rather large (about 25 m.m. long). 
1100. Dytiscus atratus, Fab., Trogus atratus, M.C.—Mainor, ovalis, anterius 
conspicue angustatus, convexus, supra niger, capite anterius prothoraceque ad latera 
testaceis; elytris vitta marginali, posterius attenuata et angustissima, testacea ; 
subtus nigro-piceus, pedibus quatuor anterioribus testaccis, tarsis intermediis piceis, 
pedibus posterioribus piceis, crassiusculis ; prosterno sulca angusta anterius dilatata 
et profunda. Long. 15, lat. 9 m.m. 
In the male the front tarsi are small, their claws are moderately elongate, and 
but little unequal, the palettes of the undersurface are small and oblong, the 
pubescent area moderately large; on the intermediate tarsi the three basal joints 
are densely clothed beneath with rather long sexual pubescence, their claws are 
simple and equal. 
This little species has a good deal of resemblance to Cybister senegalensis (No. 
1145), but is readily distinguished trom it by the sulcate prosternum. The few 
specimens I have seen of the species show little variation, in some of them the 
uppersurface has a faint metallic lustre. 
Australia, (Brisbane, Rockhampton, Clarence River, South Australia). 11165. 
1101. Cybister scutellaris, Germ., Trogus scutellaris, M.C.—Ovalis, parum con- 
vexus, supra olivaceus, capite anterius prothoraceque ad latera testaceis, elytris 
vitta marginali posterius parum arguta testacea ; subtus testaceus; pedibus pos- 
terioribus piceo-testaceis, femoribus angulo posteriori-externo acute subspinoso ; 
prosterno late obsoletissime sulcato. Long. 26, lat. 14 m.m. 
* The two following species should very probably be added to this number:—Cybister goryi, Aube 
(No. 1277 huj. op.) near No. 1100; Australia —Cybister insularis, Hope (No. 1278), near 1100; 
‘Tasmania. 
