Aa. Johnson et Mg. Kleve, TROPHOMERMIS-ITASCENSIS N-GEN, N-SP (NEMATODA, MERMITHIDAE), AN IMAGICIDAL PARASITE OF CHIRONOMIDS IN LAKE ITASCA, MINNESOTA, USA, Transactions of the American Microscopical Society, 112(2), 1993, pp. 121-127
Trophomermis itascensis n. gen., n. sp. is described from chironomid i
magos of Tanytarsus neoflavellus and Ablabesmyia (Karelia) illinoensis
emerging from Lake Itasca, Minnesota, U.S.A. The genus is distinguish
ed on the basis of being tetrapapillate, unispiculate, and hexacordal,
and in having an acute posterior terminus and a straight diagonally d
irected vagina. Additionally, the new genus lacks a cross-fiber layer
in the cuticle and has a terminal mouth and a long buccal funnel. The
amphidal openings are posterior to the small cephalic papillae. No lar
val horn is present. The trophosome is unusual in that it abuts agains
t the nerve ring and sometimes extends anterior to the nerve ring. In
the male, the trophosome extends posteriorly beyond the genital pore a
s a separated unit. Information also is provided on bionomics and vari
ants observed.