Species u . C. nr. hyperboreus

Superior volsella of Chironomus species u

Larva a medium size plumosus-type. Dark gular region and a sllightly dark to dark frontoclypeus.    Mentum with rounded teeth; c1 tooth with short sides sloping outwards, c2 teeth moderately well seperated (type I-II); fourth laterals slightly reduced (type I-II).    Ventromentum with about 44 - 53 striae.    Pecten epipharyngis with about 8 - 14 teeth.    Mandible with 3rd inner tooth well developed and darkened (type III), about 12 - 20 striations near base.    Antenna with basal segment abt 2.5 - 3.5 times as long as wide, ring organ near middle of segment; AR about 1.9 - 2.3; antennal proportions 140 : 30 : 9 : 13 : 8 .

Cytology :    4 pairs of chromosomes with the thummi arm combination AB, CD, EF, G.
Arm G mostly unpaired, with a virtually terminal nucleolus and a Balbiani ring (BR) near the other end.    No nucleoli in the long chromosomes.    Arm B with a BR near the 4 characteristic bands.

Arm A:    1-2c, 10-12, 3, 8-9, 2k-d, 4-6c, 7-6d, 13-19
Arm B:    Puff with distal dark bands (groups 7-8) near distal end of arm.    Possibly by simple inversion from B@ of C. atrella.
Arm E:    1 - 3e, 5 - 10b, 4 - 3f, 10c - 13;                        i.e. as aberratus, cucini, etc.
Arm F:    1, 5 - 2, 6 - 10, 17 - 11, 18 - 23

Click here to see the chromosomes.

Found: Alberta - Calgary.
            Saskatchewan - 5 ml. w. Theodore.
            South Dakota - 3 ml. w. Yankton, Yankton Co.

            Prairie pools.

Although the adult is similar to C. hyperboreus, the larvae and cytology are not particularly close.

Pupa with about 4 spines on the spurs.

See also C. rempeli

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