West Virginia White (Pieris virginiensis) (W.H. Edwards, 1870)

Diagnosis: The upperside of this species is dingy white and slightly translucent in appearance. The hindwing underside has the veins lined with a diffuse grey-brown scaling. The forewings are slightly rounded. Wingspan: 32 to 40 mm.

Range: The West Virginia White has a very limited North American range. It was once considered the same species as the much more widespread Mustard White (P. oleracea). In Canada, it can be found in localized colonies in southern and eastern Ontario, as far north as Manitoulin Island, Batchawana Bay north of Sault Ste. Marie, and Sharbot Lake north of Kingston. In Quebec, there are records from the Montreal area.

Specimen collection data

Description of this image follows.
West Virginia White (Pieris virginiensis). Halton County, Ont. J.T. Troubridge

Similar Species: The Mustard White (P. oleracea) has dark green scaling on the veins of the hindwing underside.

Early Stages: The larvae are light green with a yellowish-green line on each side and on the back. In Canada, they have only been recorded on Toothwort (Dentaria diphylla).

Abundance: Pieris virginiensis is never as common as the Mustard White (P. oleracea), with which it flies in some locations. However, it can regularly be found in most of its favoured locations in Ontario.

Flight Season: There is only one flight in the spring. It should be looked for in May and early June.

Habits: This butterfly is restricted to rich, moist deciduous woods, where it is easily followed once sighted as it is a weak flyer.

Remarks: Because it was known for many years in Ontario mainly from a single location in Halton County, the West Virginia White was declared an endangered species for the province. However, the discovery of many new, stable populations of this dainty white during the 1980s led authorities to remove it from the Endangered Species list in 1990.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.