260 On Aquatic Carnivorous Coleoptera or Dytiscide. 
3. Pelobius niger, Clark. Hydrachna nigra, M.C.—Convexus, sine pubescentia, 
sat nitidus niger, antennis pedibusque ferrugineis, prothorace dense fortiter 
punctato ; elytris crebre punctatis, basi rugosis ; corpore subtus fortiter punctato. 
Long. 9, lat. 53 m.m. 
I have seen only females of this species. 
Australia, (Queensland). 237. 
Ill. 1.—Tribe NOTERIDES. 
Scutellum quite invisible ; internal lamina of posterior coxa very differentiated 
from the exterior lamina, the two separated by a nearly longitudinally straight 
demarcation which extends the whole length of the coxa; the anterior border of 
the hind coxa gains its nearest approach to the middle coxa before it has extended 
in the lateral direction half way towards the epipleura: Front and middle tarsi 
conspicuously fivejointed. Anterior tibia frequently with a hook or curved spur 
at the extremity. 
(Nore.—In Notomicrus theanterior border of the hind coxa cannot be made out, the suture between it and 
the metasternum being quite obliterated, but the peculiar form of the internal lamina cannot be mistaken.) 
sq P 
( 38 { Coxo-metasternal suture obliterated ; hind ) 
z= | coxal cavities little separated ; no coxal > VOTOMICRUS (vide below). 
as Pp O 
oS line or border ( 
Pa 
BS 
Ss 0 eyste 
on Hind coxal cavities much separated ; coxal = P 5 
5 7 8 line and border present, although fine. HYDROCOPTUS (vide p. 261). 
5 A 19 ? 5 
O| 38¢ : while Th 
| s ce f Prosternal process rounded behind; hind Norerrt (vide p. 263). 
el 9) Se) femora without angular ciliz. 
Om! (©) 
= a4 3 
2) a % © | Prosternal process truncate behind; eral 
A | S Gn femora with angular cilie; hind coxal >Supuisint (vide p. 267). 
nao 219 
& Rs cavities separate. 
+e OO 
O'S & 
2 E & | Prosternal process truncate behind ; ze ) 
g Bo | femora with angular ciliz; hind coxal { HyprocaNntHInI (vide p. 268). 
l < | cavities contiguous. 
I. 2.—Genus NOTOMICRUS. 
Anterior tibia destitute of a curved spur, and with indefinite outer apical angle ; 
posterior coxal cavities but little separated, coxal notch scarcely visible. 
The extremely minute species are found in Australia and South America. 
4, Notomicrus levigatus, n. sp.—Ovalis, angustulus, subdepressus, per-nitidus, 
levigatus, impunctatus, testaceus, pectore abdominisqie basi fuscis ; tarsis posterior- 
ibus filiformibus, tibiis longioribus. Long. 13, lat. § m.m. 
I see no sexual differences in the few specimens I have seen cf this minute beetle. 
Australia, (Rockhampton, Brisbane). 468. 
