A method for recognizing the final stadium and the four preceding stadia of dragonfly nymphs (Odonata: Anisoptera) was derived by dividing hind wing sheath length (WSL) by maximum head width (HW). Based on measurements for 15 species representing all seven North American families, five stadia can be delineated, counting backwards from the final (F-0) to the four preceding stadia (F-1, F-2, F-3, and F-4). The ratio WSL/HW over all species ranged as follows: F-0, 0.89–1.39 (mean 1.16); F-1, 0.57–0.88 (mean 0.70); F-2, 0.36–0.61 (mean 0.46); F-3, 0.24–0.44 (mean 0.32); and F-4, 0.15–0.32 (mean 0.23). As a crude guide, a ratio near 1 or greater indicates F-0, about two-thirds indicates F-1, about one-half indicates F-2, about one-third indicates F-3, and about one-fourth indicates F-4. Plathemis lydia (Libellulidae) had the highest WSL/HW ratio in F-0 (1.32–1.39).
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.