Giant Sulphur

Not of concern.

One brood annually, with peak flight activity from late June to late July.

Alaska south to northern Ontario, southern Manitoba, and northwestern Wyoming (Opler 1999).

Most similar to the Pink-edged Sulphur (C. interior), but gigantea is larger (forewing length 26 - 32 mm, compared to 22 - 27 mm), with a larger discal spot and often with a more pronounced satellite spot. The shape of the forewing is also more rounded. Boreal region populations are subspecies mayi, while those from the Crowsnest Pass region southward are slightly smaller and are considered supspecies harroweri (Bird et al. 1995).

Fens, bogs and wet meadows.

The immature stages are undescribed. It is believed that larvae overwinter (Bird et al. 1995). The wet, shrubby areas inhabited by this species means it is not often observed, but road allowances through fens and bogs with regenerating willows are good places to look for this insect.

The larvae feed on willows (Layberry et al. 1998). There are no published reports of adult feeding behaviour.