About Dicerca tenebrica (Kirby, 1837)
Dicerca tenebrica has a flat head, which is the source of its name, and its vertex is slightly depressed in the middle. Both the disk and vertex are coarse and punctate. The lateral margins of its prothorax are parallel at the base and widen closer to the middle. The lateral margins near the elytra are subparallel and are wider farther from the middle. Female D. tenebrica differ from other members of the genus by having a reduced middle tooth or a complete absence of this tooth. Males measure 15–21.5 millimetres (0.59–0.85 in) in length and 4.8–7.2 millimetres (0.19–0.28 in) in width. Females range from 14.5–26 millimetres (0.57–1.02 in) in length and 4.5–9.0 millimetres (0.18–0.35 in) in width. Ecologically, this species is active as a flying adult from March to November. During this period, it feeds on poplar species, especially Populus balsamifera. In Alberta, D. tenebrica is recorded feeding on Pinus contorta, aspens, jack pines, and white spruces, and it also lays its eggs on these host trees.
