81 



the apex, having behind this section a sinuous impression, with 

 a yellow margin ; the seventh is yellow at the apex, on either 

 side deeply sinuate, the middle of the bend broad, the apex 

 strongly prolonged triangularly ; female differs chiefly from 

 male in having a much smaller head, which is also orbiculate, 

 the thorax being narrower and a little longer. Length — 2fi-3i 

 mill. 



Localities. — Western Australia, Port Augusta. 



O. semirufus, Fauvel, L, p. 34. 



Almost the size and form of complanatus, but altogether 

 distinct ; slightly depressed and nitid ; head and thorax red ; 

 abdomen a pitchy red ; elytra a lead-black ; the first four joints 

 of the antennse and the feet a testaceous red, the 3-5 joints 

 moniliform, G-10 broader, strongly transverse and thickened, 

 the 11th rather large and conical ; head transverse, thickly and 

 pretty finely furrowed, each side behind the eyes — which are 

 rather large — is bordered by a deep impression, the forehead 

 broadly depressed, in front of the clypeum slightly convex, 

 almost smooth, raised in that part above the antennae, rounded 

 anteriorly ; the top parts are more broadly furrowed ; the 

 thorax is a quarter as broad again as the head, equally long 

 with it, somewhat transverse, anteriorly a little and posteriorly 

 strongly narrowed, very rugosely and rather regularly punctate, 

 the back is ti-isulcate, the external furrows being the broader, 

 on each side pretty near the margined borders is a deep im- 

 pression, the anterior extremities truncated, the posterior ones 

 obtuse ; elytra a good deal broader than the thorax, a little 

 longer and flatter, with dense and somewhat deep strigose 

 punctation, with two keels as it were under the shoulders ; the 

 abdomen not so shiny as the rest of the body, almost aluta- 

 ceous, with a few very fine punctures. The elytra are often of 

 a smoky red. Male not known. 



Length. — 3 mill. 



Localities. — Melbourne, New South Wales, Port Augusta. 



O. sparsus, Fauvel, L, p. 35. 

 Much smaller than the preceding species, and differently 

 coloured ; a yellowish testaceous, nitid, head reddish brown, 

 thorax shining, abdomen blackish pitch, the top of the 6th 

 segment and the 7th of paler tint ; the antennse gradually 

 become rather thickened, from the 6-8 joints strongly trans- 

 verse, the 9-10 broader and not so short, the 11th conical and 

 rather large ; the head slightly transverse, suborbicular, 

 slightly convex, marked with some rather deep punctures, the 

 forehead somewhat deeply impressed, anteriorly lengthened 

 and rounded, above the antennae very much raised, convex in 



