Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

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Leuctridae - Needleflies

(adapted from Hitchcock 1974)

1a a. Supraanal process behind Ab10 tergite Males, 2
b. Posterior margin of Ab8 sternum straight
1b a. Supraanal process absent Females, 5
b. Posterior margin of Ab8 sternum posteriorly produced as a subgenital plate
2a(1a) Ab7-8 tergites with processes barely raised or absent Leuctra ferruginea (Walker)(in part)
2b Ab7 or Ab8 with a process 3
3a(2b) Ab7 tergum only with a process 4
3b Ab8 tergum only with a process 5
4a(3a) Ab7 tergal process reaching out over the anterior margin of Ab8 tergum Leuctra tenuis (Pictet)
4b Ab7 tergal process not reaching more than halfway across Ab7 tergite Leuctra tenella Provancher

Mature nymphs
(adapted from Harper and Hynes 1971)

1a Whorls of bristles on cercal segments bushy Leuctra sibleyi Claassen
1b Whorls with fewer bristles 2
2a(1b) In lateral view, only Ab3-4 tergites with short stout bristles along the dorsal margin Leuctra tenella Provancher
2b In lateral view, all abdominal tergites covered with short stout bristles along the dorsal margin 3
3a(2b) No stout bristles on the abdominal sternites, although a few long bristles are on the posterior margins of the last abdominal segments Leuctra ferruginea (Walker)
3b Short and stout bristles numerous on Ab9 sternite, a few additional scattered bristles may be present on preceeding segments Leuctra tenuis (Pictet)


    Harper PP, Hynes HBN. 1971. The Leuctridae of Eastern Canada (Insecta; Plecoptera). Canadian Journal of Zoology 49:915-920.

Page created: September 29, 2006; Last edited: November 7, 2013 (EB)