Larva: a medium sized, essentially plumosus-type larva, although lateral tubules (about 380 micron long) are more ventrally placed than in other species. Anal tubules about 425 microns long, with median constriction. Gula pale or slightly darkened on posterior third; frontoclypeus pale. Mentum (Fig. c) with c2 teeth of central trifid tooth markedly separated from c1 tooth (type II) and pointed towards it, 4th laterals at most slightly reduced (type I). Pecten epipharyngis (Fig. a) with about 12 - 13 often irregular teeth. Ventromentum (Fig. d) with about 27 - 28 striae. Antenna (Fig. b) with the basal segment about 4 times as long as wide; AR about 2.4; ratio of segments 125 : 29 : 6 : 9 : 5. Mandible (Fig. e) with third inner tooth darkened and completely separated (type III), with three spines on inner margin, and about 12 - 13 striae at the base.
The larva is most readily recognised by the unusual premandible, which has 7 teeth rather than the usual two.
Some larval characters have been illustrated by P.S. Cranston in his Electronic Guide to Chironomidae of Australia, as C. vitellinus. These are reproduced here (with permission). Cytology: 4 pairs of chromosomes, possibly with the thummi arm combination AB, CD, EF, G, but Keyl arms very difficult to recognize. Nucleolus virtually terminal in arm G, with large BR near middle of the arm; closely paired. No nucleolus in long chromosomes.
Click here for the polytene chromosomes
The pupa has been illustrated by P.S. Cranston in his Electronic Guide to Chironomidae of Australia, as C. vitellinus. This illustration is reproduced here (with permission).