Larva a small to medium plumosus- or thummi-type (may be pH dependent?), with posterior ventral tubules usually slighlty longer and coiled. Gular region slightly darkened, frontoclypeus pale. Mentum with relativley pointed teeth; centre tooth relatively broad with short parallel sides, side teeth moderately well seperated.
Cytology: 4 pairs of chromosomes with thummi
arm combination AB, CD, EF, G.
Arm G usually closely paired with a Balbiani ring about 1/3 from one
end, although specimens from South Dakota had a nucleolus immediately
distal to the BR. Nucleolus is near the centromere in
arm D. Polymorphism in arm G near distal end, homozygous
in South Dakota specimens, which are also heterozygous for an
inversion of about 2/3 of the arm.
har A1: 1a-e, 8-9, 2d-3, 15-13, 4-7, 3f-i, 12c-10,
2c-1f, 16-19; from
utahensis
by In7-8
har B1: Puff, with distal dark bands, at distal end of
arm, but lacks small BR found in proximal region in
utahensis
har E1: 1-3e, 5-7c, 10c-12, 3f-4, 10b-7d, 13;
from utahensis
by In12-10c
har F1: 1, 9-4c, 14-13c, 2a-4b, 15-17, 10, 13b-11, 18-23.
har F2: approx 1, 9-4c, 14-13c, 11-13b, 10,
17-15, 4b-2a, 18-23 (South Dakota)
Click here for the polytene chromosomes.
Found: Arkansas - 40
km sw. Little Rock, Saline Co. (plumosus-type)
Illinois - Bradley's Acid Pit, Jackson Co.
(thummi-type)
New
York - 2-2.5 km e. Middleport, Orleans Co. (plumosus-type)
South
Dakota - 3.5 km w., 5 km s. Lake Andes, Charles Mix Co.
Pools with low pH.
Morphology and cytology described by Wülker, Sublette & Martin (1991). Some ecological data given by Harp and Campbell (1973), as C. plumosus; Harp and Hubbard (1972), as C. n.sp. and Bates and Stahl (1985), as C. nr. maturus. The South Dakota population may represent a distinct species, however more samples are required to clarify this. In the meantime it is assumed that this is just geographic differentiation.