Two species of this genus of small, slender damselflies have been recorded in Michigan (see maps below). Larvae are usually found in the aquatic vegetation of the still waters of marshes, fens and sphagnum bogs. Walker's (1953) treatment for the two species remains a very recommended work. Larvae of N. irene are found among the macrophytes, sedges, cat-tails and other emergent vegetation in a wide assortment of aquatic habitats, including still areas of streams and rivers, sloughs and ponds, and sometimes bogs. I. gracilis, on the other hand, appears to be restricted to sphagnum bog habitats, with larvae found near and alongside the margins of floating bog mats. Both species may be locally abundant in their particular habitat. Adults emerge from mid-May through July.
Other links with information on the biology or
ecology of larval Nehalennia:
Brief
habitats notes from the Houston, Texas, USA area >>http://www.io.com/~pdhulce/dragon3.html
Ottawa,
Ontario survey, with brief habitat notes >>
http://www.cyberus.ca/~jdsankey/odon2.html
Map 1
Map 21a. Caudal gills with numerous small marginal spots (picture); posterolateral surface of head with about a dozen short spines, which are darker at base (picture) - N. irene
1b. Caudal gills unspotted or nearly so (picture); posterolateral surface with 4-6 small colorless spines - N. gracilis
Hagen, H. A. 1861. Synopsis of the neuroptera of North America, with a list of the South American species. Smithsonia Miscellaneous Collections 4:1-347.
Morse, A. P. 1895. New North American Odonata. Psyche 7:207-211.
Selys-Longchamps, E. de. 1850. Revue des odonates ou Libellules d'Europe. Mémoires de Société de Science de Liege 6:1-408 (reprint 1-408).
Walker, E. M. 1953. The Odonata of Canada and Alaska, Vol. 1. University of Toronto Press: Toronto, Ontario. 292 pp.
Westfall, M. J., Jr. and M. L. May. 1996. Damselflies of North America. Scientific Publishers: Gainesville, Florida. x + 650 pp.