Peculiar wing position in Dysphaea dimidiata Selys (Zygoptera: Euphaeidae)
Notulae odonatologicae , Volume 1 - Issue 8 p. 134- 135
While collecting Odonata on a series of streams north of Padawan, Sarawak, Malaysia, on 22 August 1980 I encountered several males of D. dimidiata. They seemed extremely wary, perching on branches of fallen trees 1-2 m above riffles, then flying rapidly over the stream to a new perch when disturbed. Only with considerable effort was 1 able to collect 2 males to allow identification. One of the males, watched for several minutes, perched with wings closed much as did the related Euphaea tricolor Selys on the same stream. To my surprise, another of the male Dysphaea opened its wings and held them depressed at an angle below the horizontal, very much as in the position adopted by many libellulids at rest. It performed this action at least 3 times, each time after changing its perch. The wings were depressed with a sudden movement after it rested for 10-60 seconds with wings closed, and as 1 approached closer to attempt to photograph it, it would fly again. A photograph was finally taken by extending my arms at full length over an intervening branch; it is out of focus but allows measurement of the angle of the depressed wings. This damselfly, about 45-50 mm in total length, is entirely black. The fore wings are black to the nodus, with a narrow black tip. The hind wings are black to halfway between the nodus and stigma, with a wider black tip, thus leaving a relatively narrow hyaline area. In the dried specimens, the black part of the wing is slightly iridescent, but this was not evident in sunlight in the field. The males were quite conspicuous from the side with wings folded but less so with wings open, at which time they would have been more visible from above or below. The fore wings were depressed about 40° and the hind wings about 30° below the horizontal.
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