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Damselfly Claspers & Genitalia

In this dorsal view of a Lyre-tipped Spreadwing, the paraprocts can be seen between and below the cerci.

In this lateral view of a Familiar Bluet, the cerci can be seen above the whitish paraprocts

In many cases, the male terminal appendages or claspers must be examined for definite species ID.  This is especially true of several "species pairs" of Bluets and Spreadwings in which field marks haven't yet been discovered or are so variable that the species ID cannot be made with certainty.

In some cases, the critical parts can be seen with close focusing binoculars, but most of the time in-hand examination with a small lens or loupe will be necessary.  This can be quite a challenge since on some, especially Dancers, the differences are subtle and the damselfly keeps trying to wiggle!

Note the differences in the ovipositors between Common (top) and Sweetflag Spreadwings

Some females can be identified by the shape and size of the ovipositor. This is especially true of Spreadwings which generally have quite prominent ovipositors. In a few cases, such as the Common and Sweetflag Spreadwings shown to the left, the females may be easier to ID than the males which are essentially identical, with even their claspers requiring microscopic examination to tell them apart.

Male damselflies also have secondary genitalia underneath abdominal segments 1&2 but these are of limited use in ID as are the plates on the back of the female's head which are grasped by the male's claspers.

© 2019 Sheryl Chacon Search