Larva a medium plumosus-type with well developed lateral and ventral tubules. Gular region and frontoclypeus pale or slightly darkened. Centre trifid tooth of mentum with the c2 teeth well separated, lateral teeth grading evenly to edge of the mentum (type I), although 4th laterals may be slightly reduced in some specimens.
Cytology: 4 pairs of chromosomes with the pseudothummi-cytocomplex combination AE, BF, CD, G. Centromeres not heterochromatic.
Arm G with a terminal nucleolus and two BRs towards the other end of the chromosome. Polymorphism in arms B, C, E, F and G of Palearctic material. Arm A differs between European and Siberian material (not a simple inversion), and the Alaskan sequence is the same as that in Siberia (A2). Arm E in Alaska is E2 as in Europe.
Sequences, based opn Palearctic material:
h'aciA2: 1-2c, 15-13, 10-12, 3-2d, 6c-4, 9-6d, 16-19 Siberia (Kiknadze et al. 1996)
h'aciB1: No obvious puff, but dark bands distally.
h'aciC1: 1a-e, 13e-11d, 21-17b, 7a-d, 16-17a, 15-13f, 5c-6, 11c-8, 1f-5b, 22 Siberia
h'aciD1: 1-2g, 13-15b, 17-15c, 7-2h, 12-8,18-24 Siberia
h'aciE2: 1 - 3e, 10b - 3f, 10c - 13
i.e. as luridus, etc.
h'aciF1: 1, 11 - 12, 19 - 16, 2 - 10, 15 - 13, 20 - 23
Click here for the polytene chromosomes.
Found: Alaska – Potters Marsh, Anchorage Co.
Also described from Reinbeck, Germany, and Yakutia, Russia.
Supposedly only occurs in acidic waters.
A species with a Holarctic distribution.
The karyotype, with a heterozygous inversion in arm C, was first figured by Keyl (1960), then the sequences of arms A, E and F for European species given by Keyl (1962), and karyotype of Siberian specimens, as species Ya4, by Kiknadze et al. (1996) and revised by Kiknadze et al. (2004).