LANCEIMERMIS-MINNESOTENSIS N-SP AND GASTROMERMIS-PARVISPICULARIS N-SP(NEMATODA, MERMITHIDAE) FROM ADULT CHIRONOMIDS EMERGING FROM LAKE ITASCA, MINNESOTA, USA

Lanceimermis minnesotensis n. sp. and Gastromermis parvispicularts n. sp. are described from adult chironomids emerging from Lake Itasca, Mi nnesota in June 1992. L. minnesotensis n. sp. is distinct from other m embers of the genus in the presence of a subventral mouth, location of the amphidal opening immediately posterior to the level of the cephal ic papillae, presence of an excretory pore, presence of a dorsal commi ssure, and in the presence of supporting ligaments between the amphids and the anterior esophagus. Additionally, the terminal denticles on t he non-ornamented spicule and the organization of the copulatory muscl es serve to readily separate the males. A new combination L. canadensi s is introduced. G. parvispicularis n. sp. is separated from other mem bers of the genus by body length, esophagus length as a percentage of body length, six hypodermal cords, long buccal funnel, amphidal openin gs at the level of the cephalic papillae, suspensory ligaments between the anterior esophagus and the amphids, presence of a dorsal commissu re, absence of an excretory pore, small size of the spicule, and short terminal limbs of the vagina. The practice of using only one sex or s mall numbers of specimens for species descriptions is discouraged.