Figs 25A–F
Diagnosis. SI seta simple; premandible (Fig. 25A) simple without brush; antenna (Fig. 25B) 5-segmented with short segment 2 and large LO exceeding the length of 3 rd, AR 1.1; mandible (Fig. 25C) with very weak crenulation on outer margin; mentum (Fig. 25D) unique with enlarged conical median tooth taking up most of mentum and 2 small basolateral teeth; no indication of VM plates; abdomen with well defined setal tufts (Fig. 25E); posterior end of abdomen as in Fig. 25F; anal tubules, long cylindrical.
Notes. The median tooth of the mentum has a bifid apex, which so far has not been reported for this species and the abdomen has setal tufts on AII–AVII, compared to AI–VI in Cranston (1982). The species has been placed as a subgenus of Orthocladius by Saether (2003).
Ecology and habitat. A xylophagous species common in streams with large quantities of wood, especially maple (Cranston & Oliver 1988, Saether1983). In the stream sites larvae occurred mainly in pools where submerged woody debris was abundant.
Sampling sites. Mississagi, Massasauga and Arrowhead Provincial Parks.
Nearctic distribution. Canada: British Columbia, Manitoba, Québec, Saskatchewan, Yukon Territory, first Ontario record. USA: Alabama, Alaska, California, Florida, Georgia, Maryland, Minnesota, New Hampshire, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia, Wisconsin.