Figs 42A–F

Diagnosis. Head capsule, including posterior margin pale; and premandible as in Fig. 42A; SI seta divided; premandible with single tooth; antenna (Fig. 42B) 5-segmented with segment 3 slightly shorter than segment 4 (Fig. 42C); mandible (Fig. 42D) with 2 short inner serrations; mentum (Fig. 42E) with bifid median tooth and 5 lateral teeth; VM plate narrow, curved distally and connecting basally to a dark circular plate; abdomen (Fig. 42F) with long setae, about half the length of respective segment; procercus well developed, twice as long as wide; anal tubules short, about half the length of posterior parapods.

Notes. In our specimens the antennal segment 3 is not as short as indicated in Epler (2001) and segment 5 is attenuated apically giving the appearance of a 6 th segment. The ventromental plates are connected basally to dark circular plates as shown in Bode (1983: 15, upper right figure).

Ecology and habitat. Based on Berg & Hellenthal (1991) this species has an asynchronous life history with indistinguishable overlapping cohorts. This species is common in mountain streams and coastal plains (Epler 2001). Larvae of T. paucunca are reported as collector-gatherer and tolerant of organic pollution (Fiorentino 2005).

Sampling sites. Massasauga Provincial Park

Nearctic distribution. Canada: NWT, Yukon, Alberta, Manitoba, and Ontario. USA: Georgia, Michigan, Ohio, North Carolina, South Carolina.