Quantitative analysis of certain wing and genitalia characters of Pieris in western North America

First record in Quebec for the western white, Pontia occidentalis (Reakirt) (Lepidoptera: Pieridae, Pierinae)

“…In Canada, the species currently ranges from British Colombia to Ontario, with only one record in Quebec dating back to 1921 in Montreal, and one other record in Newfoundland and Labrador in 2001 (GBIF.org 2024). The color and patterns of P. protodice and P. occidentalis are commonly indistinguishable (Chang 1963). According to Chang (1963), the two primary criteria for distinguishing the two species are the width of the tornus dot and the location of the R2 veins in relation to the M2 veins.…”

“…The color and patterns of P. protodice and P. occidentalis are commonly indistinguishable (Chang 1963). According to Chang (1963), the two primary criteria for distinguishing the two species are the width of the tornus dot and the location of the R2 veins in relation to the M2 veins. In P. protodice males, the dot in the tornus area near the inner margin of the underside of the forewings is often large, square shaped and not clearly outlined, with part of the dot sometimes submerged on the upper sides.…”

“…2. Illustration of differences in dorsal anterior wing venation between Pontia protodice and Pontia occidentalis adapted from Chang (1963). In P. protodice, intersection between R2 and Rs + M1 (A) is usually above (B) where M2 joins the vein.…”

“…2019). The current note reports the recent discovery of seven specimens of Pontia occidentalis (Reakirt, 1866) sensu Chang (1963), at the mouth of the Rupert River in Eeyou Istchee James Bay, near the village of Waskaganish, Quebec, Canada. While these records are not surprising given the current species biogeography, they represent the first record for the genus Pontia in the province of Quebec since 1921.…”