Heleniella sp.

Namayandeh, Armin, Bilyj, Bohdan, Beresford, David V., Somers, Keith M. & Dillon, Peter J., 2012, 3324, Zootaxa 3324, pp. 1-65 : 28

Heleniella sp.

Figs 21A–F

Diagnosis. Labrum as in Fig. 21A; SI seta divided distally; SII seta robust simple; premandible with two apical teeth; antenna ( Fig. 21B) 5-segmented, 2 nd segment has unsclerotized annular ring near the base, 3 rd strongly reduced and completely enveloped by LO, blade long surpassing the length of flagellum, AR 1.2; mandible as in Fig. 21C; mentum ( Fig. 21D) with large pair of median teeth, 5 laterals with second last one recessed, base with notch and small projection; VM plate ( Fig. 21E) appear to be fused with mentum, only the outer margin is defined, anteriorly makes connection with first lateral; posterior end of body as in Fig. 21F; procercus with 7 apical setae, including two distinctly shorter than the rest; supraanal setae located between the procerci.

Notes. The single larva collected has antennal segment 3 barely discernible, about the size of the peg sensilla of the Lauterborn organs. There are no species keys to separate the larvae, but from the distributions of the three known Nearctic species, the most likely candidate would be Heleniella hirta Saether that was collected from nearby Algonquin Park, Ontario ( Saether 1969).

Ecology and habitat. Typically occurs in low order streams in winter and early spring ( Hudson et al. 1990). Larvae occur in streams with temperature ranging from 6.9°C to 12.6°C ( Rossaro 1991).

Sampling sites. We found the larvae inhabiting streams in all the provincial parks and districts located in our study area.

Nearctic distribution. Canada: Ontario.