SeasonalitySpecimens have been collected from late June to early August.
IdentificationAdults (Teskey 1990): Females are 7-10 mm in length, and are patterned orange and black overall. On the head, the frons is slightly higher than wide; the ocellar prominence with extensive glossy black area; the antenna black except for the the orangish scape (or even a few segments higher on the antenna); clypeus entirely yellow; palpi brown. The thorax is covered with yellow hairs and is distinctly striped with grey and black; the front coxa and mid and hind tibia, femora, and basitarsi are blackened, remainder yellowish; on the wings, the apex of the basal radial cell is clear while the basal portion and the basal median cell are infuscated (pigmented). On the abdomen, the black spot on tergum 1 is joined to the geminate (doubled) spot on tergum 2 which encloses a median yellow triangle; tergites 3-7 are black anteriorly with yellow posterior margins.
The males are similar to the females, except they are smaller, the scutum is nearly black, there are medial black figures on tergites 1-2, and abdominal segment 1 does not constrict at all when it joins to the thorax.
Chrysops furcatus is superficially similar to C. coloradensis, C. montanus, and C. lateralis, none of which are found in Alberta. However, it can be separated morphologically from those three by wing venation: C. furcatus lacks of infuscation in the apex of the basal radial cell, and the hyaline triangle crosses multiple radial cells (Teskey 1990).
Larvae (Teskey 1969): creamy-white, 15-17 mm in length. It is separated from other Chrysops spp. by the presence of a posterior pubescent annulus extending from the anal segment, making up 1/3 of the length of the segment, and by the length of the respiratory siphon being twice the diameter at the base.