Diagnosis: Until recently this species was thought to be the summer "form" of the Spring Azure. The upper surface is pale blue with an extensive dusting of white scales, especially on the hindwing. In some females the blue is almost entirely replaced by white with a small amount of blue near the wing bases. Females have a broad blackish-grey band on the outer third and costa of the forewing. The underside is chalky white to pale grey with tiny dark grey spots and a zigzagged submarginal line on the hindwing. Wingspan: 23 to 29 mm.
Subspecies: The nominate subspecies neglecta occurs in southeastern Canada. Subspecies argentata is whiter underneath than subspecies neglecta, with very tiny dark dots; it occurs in southern Manitoba and Saskatchewan.
Range: The Summer Azure occurs across southern Canada from Nova Scotia to southern Saskatchewan.
Similar Species: See discussion under the Spring Azure (C. ladon).
Early Stages: These are similar to those of the Spring Azure except that the overwintering pupa does not emerge in the spring when the weather warms up; instead, the pupal resting phase (diapause) is extended until early summer. The larvae feed on species of flowering shrubs that are in bloom in late spring and summer, such as dogwoods (Cornus spp.), New Jersey Tea (Ceanothus americanus), meadowsweet (Spiraea spp.) and late-blooming viburnums (Viburnum spp.).
Abundance: The Summer Azure is common to abundant in southern Ontario but less common than the Spring Azure in most other areas.
Flight Season: Adults are on the wing from mid-June until early September with two or three generations. Second- and third-generation adults are rare except in southern Ontario.
Habits: Adults are found in open woodlands, like the Spring Azure, but are also commonly found in more open areas such as city parks and weedy fields.
Remarks: The Summer Azure was formerly thought to be a second-brood form of the Spring Azure. Most pupae of the Spring Azure enter a resting phase and do not emerge as adults until the next spring. Summer Azures have successive generations as long as weather permits, but the overwintering pupae have an extended resting phase, so that the adults do not emerge until early summer. In some areas, such as extreme southwestern Ontario, the Spring Azure is rare and could not possibly produce the numbers of Summer Azures that abound in the area in the summer.
© 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.
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Date Modified: 2010-05-31