Larva a medium sized plumosus-type (lenght female about 12.2 mm), ventral tubules quite long (Female: Ant about 1.48 mm; post about 1.76 mm). Dark gula and pale or slightly darkened frontoclypeus. Mentum with pointed teeth, centre tooth quite broad and parallel sided, c2 teeth well separated and pointed (type II); 4th laterals reduced (type II-III). Pectin epipharyngis with about 12 - 13 relatively broad teeth. Wülker (1996) described the larva of Scandinavian specimens as a plumosus-type, about 15 mm in length. Head with diffusely dark clypeus, hind part of gula with a dark oval spot. Lateral tubuli on abdominal segment VII less than 1/5 of the length of the segment.
Cytology: 4 pairs of relatively short chromosomes with
distinct heterochromatic centromeres. Arm combination is
thummi-cytocomplex, AB, CD, EF, G. Banding pattern not
clear in available specimens.
Arm G is closely paired with a constriction near the heterochromatic end, and
a dark group of bands near the middle of the arm. No
distinct nucleolus or Balbiani ring in G. Nucleoli
developed in all three larger chromosomes, in arm B, proximal in F, 2
in D and a terminal nucleolus is sometimes present in C.
In the Palearctic, polymorphism has been reported in arms A, B and D
(Kiknadze et al. 1996).
In North America, so far, polymorphism has only been reported in arm
D in the region of the nucleoli.
pil A1: 1 - 3i, 12c - 4a, 13a - 19f
i.e. as pseudothummi
pil B1: 1-2d, 3-2e, 20-18, 21-22, 6-8a, 5-4, 8b-13,
17-14, 23-28
pil C1: 1-6b, 11c-8, 15-11d, 6gh, 17a-16, 7d-a, 6f-c,
17b-22 i.e. as aberratus,
tenuistylus, etc
pil D1: 1 - 3, 11 - 18d, 7 - 4, 10 - 8, 18e - 24
i.e. as in longstylus,
cucini, atrella D1
pil E1: 1a - 3e, 10b - 3f, 10c - 13g
i.e. as in aprilinus, atrella, athalassicus
pil F1: could be 1 - 6, 12 - 7, 13 - 23
i.e. as Palearctic pilicornis
Click here for the polytene chromosome CD
Found: Alberta -
Rosebud; Waterton Lakes (based on adults)
Manitoba - Erickson; Southern Indian Lake (Rosenberg et al. 1984)
North
West Territories - Trough Pond, Horton River area (M.G.Butler,
pers. comm.)
Saskatchewan - Oxbow, Saskatoon Townes (1945)
South
Dakota - Emanuel Cr., 2. ml W of Springfield (Sublette, pers.
comm.)
Also found in the
Palearctic, type locality Kiel, Germany.
Prairie sloughs and pools.
The chromosomes have been described for Palearctic material from Europe by Wülker (1996) and from Siberia by Kiknadze et al. (2002, 2004). Although the chromosomes of North American specimens are essentially identical to Palearctic C. pilicornis, a rearing from Rosebud, Alberta was not C. pilicornis. However it remains to be proven that the rearing was conspecific with the larvae used for cytological analysis. Description of adult in Townes (1945).