Idenfitication: A large spreadwing. Dull overall compared to Great Spreadwing with blue eyes and a prominent whitish stripe along the side of thorax. See Similar Species for more information on separating this species from Great Spreadwing.
Size: Total length: 47-59 mm; abdomen: 36-44; hindwing: 30-37 mm.
Similar Species: Pond spreadwings (Lestes) are smaller with the length of the hindwing less than 30 mm. Also most Pond Spreadwings in the range of California have a thorax that is dark above and light below.
Similar to Great Spreadwing. With practice, both males and females can be identified in the field based on the distinctive color pattern of the thorax. In California, the stripe along the side of the thorax is whitish and does not extend back to the base of the wings. It is bordered above by a prominent rectangular metallic greenish-gray patch that contrasts with the tan or brown background color of the thorax. In Great, the throacic stripe is yellowish-white and extends all the way to the base of the wings. The remainder of the upperside of the thorax is metallic greenish, gray or bluish.
Male appendages are diagnostic: in California the short paraprocts (lower male appendages) are easily visible from above between the large, long black cerci. In Great Spreadwings the paraprocts are hidden under the cerci and are not normally visible from above.
Habitat: Small permanent ponds or streams with slow or moderate flow
Natural History: This species was known only from the southwest United States up until the 1920's, but it has since undergone a dramatic range expansion northward. It now occurs as far northeast as western New England. One study showed that that neither males nor females exhibited any type of courtship behavior, and unreceptive females showed no refusal signs, but rather were simply not at the water or escaped by rapid flight when unreceptive. No pairs were observed ovipositing from beginning to end, but the longest observed egg-laying time was 109 min.
Distribution: From the Cape District of Baja California, through California (except deserts), Oregon and south-central Washington; also the mountains of Sonora north to se Arizona, extreme sw New Mexico.
David Bell (06/21/2016)
