Cytology: 3 polytene chromosomes with the modified pseudothummi arm combination AEG, BF, CD.
Arm G with medial nucleolus, with adjacent BR and other BRs more proximal. Other nucleoli in arms A (NOR about region 18), C and F (NOR about region 22).
Polymorphism in arms A, B (often sex linked), D, F, and G.
dupA1: 1a-e, 4c-a, 12a-c, 3i-f, 9 - 8a, 2d - 3e, 1f - 2c, 10a - 11, 4d - 7, 13a -18(NOR)- 19
dupA2: an overlapping inversion or transposition.
dupB1: Puff and proximal dark bands (groups 7-8) about middle of arm as in oppositus and australis
dupB2: Puff separated from dark bands to near tip of arm by an inversion and transposition.
dupC1: nucleolus about one third from centromere.
dupD1: 1 - 2, 16 - 10d, 3 - 10c, 17 - 24
dupD2: 1 - 2c, 17c - a, 10c - 3, 10d - 16, 2h-d, 17d - 24
dupD3: 1 - 2c, 8 - 10c, 17a-c, 7 - 3, 10d - 16, 2h-d, 17d - 24
dupE1: approx. 7d - 6; arm G; 4(f-a?), 5?, 7e - 10b, 3e - 2c, 4gh, 3f, 10c - 13
dupF1: 1 - 2a, 10 - 2b, 11 -22(NOR)- 23 sequence as oppositus F1
The arm B sequences are clearly sex linked in some, southern, populations such that most females are homozygous B1.1, while most males are heterozygous B1.2. In more northern populations the majority of individuals are B2.2, with little evidence of sex linkage (Martin, 1971b).
Larva morphologically very similar to those of C. australis and C. occidentalis. Separable from the former by the difference in chromosome number, and from the latter by eastern distribution.
Pupa: General coloration is dark. Various characters are given in the Table below.