Species 3n. C. longistylus Goetghebuer 1921

Adult:
(based on European specimens in Wülker 1991)(NB: Langton & Visser note that there are differences between the male (sensu Wülker) and those shown on Goeghebuer's original figures)

Male:
Black, with a dark Superior volsella.  Anal point may be less slender than that of C. tenuistylus.
Wing length 4.22 (4.15-4.30) mm.
AR 3.8-4.5; anterior LR 1.33-1.53; BR 2.41-3.1
Frontal tubercle 30-40 µm in length.
Setae: acrostichal 19-25; dorsocentral 33-44; prealar 7-14; scutellar34-53.
Tergite IX with 5-14 setae, possibly in individual pale areas.
The Superior volsella of this form is shorter and more club-shaped than the longer narrower type figured by Goetghebuer (e.g. Fig. 144C of Pinder 1978, below); dark and closest to E(g) type of Strenzke (1959); Inferior volsella reaching almost to end of the parallel-sided anal point, or about halfway along the gonostyle, which is moderately swollen and narrows relatively gently over posterior third.  Anal point essentially parallel-sided.

Female:
Wülker (1991) Fig. 9 shows the cercus to have a relatively pointed posterior end, with a significant ventral bulge.

Pupa: (based on Palearctic specimens from Langton & Visser, 2003):
Exuvial length 9.7 mm (7.2-11.8) mm.  Color golden brown to dark brown, difference in color between thorax and abdomen not marked, outer margin of anal lobes colored except at bases.
Cephalic tubercles 108x110-200x185 µm; frontal setae30-82 µm long, basal ring of thoracic horn 176 x 77 (120x60-200x80) µm; HR 2.28 (2.13-2.50).
Hook row of segment II entire, occupying 0.47-0.53 of the segment width, with about 68-99 hooks.  Armament of tergits not extensive, that of tergites II-VI in form of an undivided, usually extensive patch of strong points, the points in each segment increasing in size posteriorly, the point patches increasing in size from II-V; points of VIII mainly isolated and irregularly arranged.  Seta D4 of TVI closer to midline than seta D3.  Lateral spur of segment VIII with 1-4 stout apiculate teeth.  Anal lobes weakly rounded with 110 (66-140) fringe taeniae, and 1(2) dorsal taenia.

Fourth instar larva of the plumosus-type but smaller than C. tenuistylus.
Gular region darkened only at posterior; frontoclypeus pale; ring organ about 0.3 of the distance from the base of antennal segment 1.

Cytology:  4 polytene chromosomes with the thummi arm combination AB, CD, EF, G.  Centromeres heterochromatic.
Arm G generally unpaired with a nucleolus near the heterochromatic centromere, the other end forming a fan-like structure terminated by dark bands, 2 Balbiani rings near the nucleolus.  A nucleolus is also present in arm C.
Polymorphism known in arms B (Holarctic), D, F & possibly E (Nearctic).
lonA1:    1 - 2c, 10 - 12, 3 - 2d, 9 - 4, 13 - 19                    i.e as holomelas, tenuistylus, etc.
lonB1:    1 – 8a, 21 - 16?, 8b – 15, 22 – 25                      i.e. as staegeri, 'tigris'B1 (Kiknadze)
lonC1:    1-6b, 11c-8, 15-11d, 6gh, 17a-16, 7d - a, 6f - c, 17b-22        ie. as aberratus, tenuistylus, etc.
lonD1:    1 - 3, 11 - 18d, 7 - 4, 10 - 8, 18g - 24                ie. as tardus, cucini, pilicornis.
lonE1:    1 - 3e, 5 - 10b, 4 - 3f, 10c - 13                            i.e. as tenuistylus, etc.
lonF1:    1 - 23                                                            i.e. Standard, as piger, sp. 3b, etc.
lonG1:    Heterochromatic centromere, with nearby nucleolus and 2 BRs.

Found: Newfoundland & Labrador - Torngat Mountains National Park (58.4505°N, 62.7982°W) (BOLD)
            Northwest Territories - Nailoicho, Nahanni National Park (61.606°N, 125.758°W) (BOLD).
            Yukon Territory - Ivvavik National Park (69.162°N, 140.155°W); Kluane National Park (60.748°N, 137.513°W) (both BOLD).
            Alaska - No name Lake, Haul Road, South Slope.

Morphology and cytology described by Wülker (1991a).