This specimen was examined when in the collection of the Macleay Museum and some additional details recorded. Since the Skuse description, the antennae and the remains of the hind legs have been lost:
Wing length (measured from brachiolum, consistent with my other wing measurements) 6.26 mm. Palps (segments 2-5 in micron): 70 : 270 : 250 : 430: P5/P4 1.72, P5/P3 1.59.
Thoracic setae could not be counted accurately but there were at least 14 dorsocentrals and at least 5 prealars.Leg lengths (micron) and proportions:
Note: type specimen is a female. The descriptions below include the first description of the adult male, as Freeman (1961) synonymised the species with Chironomus australis McQuart.
Superior volsella closest to E(h) type of Strenzke (1959); Inferior volsella reaching at least half way along the gonostylus, with simple setae. Gonostylus moderately swollen and reducing gently over about the posterior third to half; with 7+1 setae at distal tip. Anal point narrow and darkened.
Abdomen with darker band, sometimes extended a little posteriorly in the midline, over the anterior 2/3 of segments I-VI, then over most of tergite. GcIx with 3-7 setae; SegX curved and 3.9 (3.34-4.30) times longer than wide, with 15.9 (12-20). Cercus with a generally curved outlinewith a large ventral and a small dorsal basal bulge.
Morphologically very similar to C. australis and C. duplex, but is distributed allopatrically to them on the west of the continent.
The adult is about the same size as C. australis and slightly larger than C. duplex
C. occidentalis can be readily separated from C. duplex at the pupal stage on the basis of the pupal spurs, in which the spines (about 5-6) are closely applied in C. occidentalis but spread in C. duplex. The pupal spur of C. occidentalis resembles that of C. australis.
Found: Northern Territory: Magela Creek, Mudginberri Station (12.75°S, 132.88°E).
Western Australia: King George Sound (Holotype location)(35.03°S, 117.93°E); Cape Naturaliste (32.53°S, 115.03°E);
Crawley (31.99°S, 115.82°E); 3 Km w. Esperance (33.85°S. 121.87°E); Lake Monger (31.93°S, 115.826°E),
Township of Cambridge; Lake Sepping, Albany (33.85°S, 152.87°E); Upper Swan (31.77°S, 116.03°E).