Species j.  C. decorus group

Reared specimens are in the J. E. Sublette collection in the Museum of the University of Minnesota, St. Paul, Minn.

Only a photograph of the terminalia is available.

Male terminalia of C. sp. j.

About 9 setae in a central pale patch on TIX, probably in separate patches.  A typical C. decorus-type hypopygium, with Superior volsella similar to that of C. bifurcatus and C. maturus (D-type of Strenzke, 1959).  Inferior volsella appears slightly curved, extending beyond the end of the anal point to about midpoint of the gonostyle which narrows sharply from half to two thirds along its length.

Female: No information available.

Pupa: postero-lateral spur on segment VIII with about 4 spines.

Fourth instar larva a medium size (fem. 12.9-14.1; male 12.1-13.6) thummi-type, with anterior ventral tubules longer (ant. 1.68 (1.30-1.99); post. 1.56 (1.2-1.91)).  Lateral tubules absent.  Anal tubules about 455-530 µm long and 3-3.5 times longer than wide, with a slight constriction in the middle, ventral pair thinner than the dorsal pair (hence with higher length to width ratio).
Dark posterior half to two thirds of gular region and extending whole lateral width, with a slightly convex anterior margin and usually widest anterior to the posterior margin of the head capsule, and frontoclypeus pale or with darkened edges.
Oesophageal aperture about 74.4 (63-84) µm long and 3.3-4.7 times longer than wide.
Mentum (Fig. d) with rounded teeth;  4th laterals reduced almost to height of 5th laterals (type II);  c1 tooth high and fairly narrow, c2 teeth only moderately separated (type III, but may appear as Type IB (as Fig. d) or IIA due to wear).
Ventromental plates (Fig. b) 210.4 (195-229) µm wide and 3.2-3.6 times wider than deep, 1.09-1.18 times the mentum width; separated by about 0.3 of mentum width, with about 39-48 striae; VMR about 0.22-0.36.  Pecten epipharygis (Fig. a) with about 9.6 (8-16) relatively broad teeth, of type B when not worn.
Premandible (Fig. a) with inner tooth about 3.3-4.8 times the width of the outer tooth, which narrows markedly along its length.
Antenna (Fig. c) with A1 relatively short, only about 0.3-0.4 of the VHL, about 2.7-3.5 times longer than wide, Ring organ about 0.3-0.4 up from base; AR about 1.89 (1.63-2.24); A4 about 20-50% longer than A3, which is usually longer than A5; proportions (µm) 112.5 : 30 : 9 : 12 : 7.
Distance between antennal bases (mean 158.8 µm) about the same as the distance between the S4 setae (mean 156.9 µm), i.e. both are equally likely to have a higher value. S4 setae separated by 83.3 (76-88)% of the FC width.  S5 setae usually about level with the nearby RO, and equally likely to be anterior as to be posterior to it.
Mandible (Fig. e)with 3rd inner tooth pale or slightly colored and partly separated (type IIB); about 18 (14-22) furrows on the outer surface at the base, 12.1 (10-13) taeniae in PecM, Mdt-Mat 27.4 (20-33), MTR 0.33 (0.24-0.39).

Cytology:  4 polytene chromosomes with thummi arm combination AB, CD, EF, G.
Centromeres obvious but not heavily heterochromatic.
Arm G largely unpaired, although may be paired in middle.  Nucleolus subterminal, Balbiani ring subterminal at the other end.  No nucleoli on other arms but large distal puff (gp. 7) in arm B.
Polymorphism at least in arms A, B and D.
Arm A1:
Arm A2:  Simple inversion near the centromere.
Arm B1:  Puff (group 7) distal.
Arm B2:  Simple inversion of about 1/3 of arm just distal to middle of arm.
Arm C1:
Arm D1:
Arm D2:  Could be a complex inversion.
Arm E1:  possibly 1 - 3e, 9 - 10b, 4 - 3f, 10c - 11a, 5 - 8, 11b - 13
Arm F1:
Arm G1:  Subterminal nucleolus.

Arm G and part of heterozygous arm A of C. sp. j

Found: New Brunswick - Kouchibouguac National Park (46.858°N, 64.975°W).
            Ontario - Algonquin Provincial Park (45.58°N, 75.70°W), Nipissing Co.; Bear Creek, nr. Carlsbad Springs (45.37°N, 75.47°W),
            Carleton Co.
            Quebec - Notch Road, Gatineau Park (45.92°N, 75.60°W).

            Slow moving creeks and pools.

See also C. bifurcatus,  C. sp. b,  C. sp. c,  C. sp. 2a,  C. sp. 2b,   C. 'butleri',  C. sp. 3h,  C. sp. 3i,  C. sp. 3j,  C. sp. 3r,  C. decorus Joh.,  C. harpi,  C. blaylocki,  C. decorus R & F.,  C. mozleyi,  C. winnelli.

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Modified: 14 August 2021
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