Original description of Chironomus occidentalis from Skuse 1889
A large species with the anterior tarsi of the male strongly bearded; Leg ratio about 1.2 - 1.3.
Antennal ratio (AR) about 3.33 - 4.29.
Frontal tubercles present, length about 28 - 70 micron; 25 - 45 clypeal setae.
About 12 - 15 achrostichal setae; 13 - 27 dorsocentral setae; 5 - 9 prealar setae.
Scutellum with setae in two rows; anterior with 8 - 16 setae (higher numbers generally in two rough rows), posterior with 14 - 19 setae.
Wing length 4.72 - 6.18 mm; VR about 1.02 - 1.08.
Leg lengths (microns) and proportions as follows:
|
|
Fe |
Ti |
Ta1 |
Ta2 |
Ta3 |
|
PI |
1830 |
1778 |
2226 |
1186 |
880 |
|
PII |
2029 |
1961 |
1142 |
682 |
503 |
|
PIII |
2459 |
2507 |
1691 |
1496 |
762 |
|
|
Ta4 |
Ta5 |
LR |
F/T |
BR |
|
PI |
770 |
386 |
1.19-1.32 |
0.99-1.06 |
4.21-7.08 |
|
PII |
356 |
265 |
0.56-0.64 |
1.00-1.08 |
|
|
PIII |
487 |
296 |
0.65-0.70 |
0.96-1.02 |
|
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.
Western Australia: Cape Naturaliste; Crawley; 3 Km w. Esperance; Lake Monger; Lake Sepping, Albany; King George Sound (Holotype); Upper Swan.