Mexican Yellow
Eurema mexicanum (Boisduval, 1836)

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Diagnosis: This small sulphur (wingspan: 33 to 44 mm) is the only pierid found in Canada with a suggestion of tails. It has cream-coloured wings with black borders that resemble the shape of a wolf's head on the forewings; there is usually some yellow near the wing base.

Range: Although mainly a Mexican butterfly, this species strays northward regularly into the central and southwestern U.S. It has only reached Canada on a few widely scattered occasions, once at Point Pelee, Ontario, in 1882, and five times in southern Manitoba. There is also one Saskatchewan record from near the town of Somme.

Similar Species: The Southern Dogface (Zerene cesonia) is mainly yellow, larger, and has no tails. [compare images]

Early Stages: The pale green larva feeds on various species in the pea family (Fabaceae) that do not occur in Canada.

Abundance: The Mexican Yellow is a very rare stray in Canada.

Flight Season: Recorded dates for this butterfly in Canada range from 28 June to 29 September.

Habits: A highly migratory butterfly, this species would most likely be found in dry, open areas.

© 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.

The Toronto Entomologists' Association thanks Agriculture and Agri-Food Canada for providing the content and computer code for this web page.