C. alternans Walker, 1856

Walker's description of C. alternans, with the translation by Skuse 1889

This specimen is in the British Museum of Natural History.

To the above description can be added:
Head - Face yellow, palps and antennae brownish.  AR about 3.05, Palps (µm): 200? : 73 : 252 : 263 : 431.  Frontal tubercles 37 x 15 µm.  Clypeal setae 31.
Thorax green yellow, vittae, postnotum and sternopleuron brown.  Length abt. 1.84 mm, width about 0.94 mm, depth about 1.68 mm.
Setae - Acrostichals at least 7; Dorsolaterals 15 in 2 rows; Prealar 5,7; Supraalar 1; Scutellar ant. row 4, post. row 12.
Pronotum broad, apically tapered, then abruptly widened at the apex, anteriorly with a broad notch.  Mesonotum with a barely discernable median tubercle.
Wing length 4.36 mm; width 0.94 mm; VR 1.0.; SCf on brachiolum 3.
R4+5 ends level with M; R2+3 evanescent at tip, ending at 0.25 of the distance between the apex of R1 and R4+5; Anal ends distal to f-Cu at 0.77 of the distance between f-Cu and apex of Cu2; anal lobe well developed, right angled; squama fully fringed.
Halteres yellowish, width 205 µm.
Legs yellow, tarsi becoming brown.  Lengths (microns) and proportions as follows:

Type locality: New South Wales

Morphologically very similar to a number of other described species, some unplaced and put as synonyms by Freeman (1961), others grouped as the C. alternans-group.