Metriocnemus van der Wulp

A key to the known fourth instar larval stages of North American Metriocnemus van der Wulp 1. Mentum with 4 small median teeth and 5 pairs of lateral teeth (Epler 2001: page 7.86, couplet 2(1’))................................................................................................... M. knabi Coquillett, 1904 - Mentum with bifid or simple median tooth and 4 to 5 pairs of lateral teeth........................................ 2 2. Mentum with simple median tooth and 5 pairs of lateral teeth (Saether 1989: Figure 12G)...... M. ursinus (Holmgren, 1869) - Mentum with bifid median tooth and 4 to 5 pairs of lateral teeth................................................ 3 3. Mentum with a wide bifid median tooth and 4 pairs of lateral teeth (Fig. 3h)...................... M. erthranthei sp. nov. - Mentum with narrow bifid median tooth and 5 pairs of lateral teeth.............................................. 4 4. Median tooth of the mentum is comparatively small, sitting much lower than lateral teeth............................ 5 - Median tooth of the mentum comparatively well-developed, sitting slightly lower or higher than lateral teeth............ 6 5. Basal antennal segment no longer than wide (Saether 1989: Figure 12B). Labral lamella and SI simple (Saether 1989: Fig. 12D). Median tooth of mentum sunken (Epler 2001: page 7.86, couplet 3(2’); Orendt & Bendt 2021: page 119, couplet D7; Saether 1989: Fig. 12H). Anal tubules long and slender (Saether 1989: Fig. 12J)..................... M. fuscipes (Meigen, 1818) - Basal antennal segment longer than wide (Fig. 7b). Labral lamella comb-like and SI trifid (Fig. 5c). Median tooth of mentum not sunken (Fig. 7e). Anal tubules short and wide (Fig. 7f)......................................... M. sp. “ Oregon ” 6. Antenna 4 segmented (Cranston & Judd 1987: Fig. 4a). Basal antennal segment L/W> 4. Median tooth of mentum stands higher than 1 st lateral teeth. Setae submenti aligned with the 3 rd lateral teeth of mentum (Cranston & Judd 1987: Fig. 4c)............................................................................ M. yaquina Cranston & Judd, 1987 - Not with the above combination of characters............................................................... 7 7. Abdominal segments with long setae, each half as long as the segment bearing it.................... M. sp. A Epler, 2001 - Abdominal segments without long setae................................................................... 8 8. Procercus as wide as long or wider than long.AR 1.7–1.8. Basal antennal segment L/W: 2.3 (Th. Bendt & H.K.M. Moller Pillot, in litt.)................................................................................ M. tristellus agg. * - Not with the above combination of characters............................................................... 9 9. Median bifid tooth of mentum as high as the 1 st lateral teeth (Saether, 1989: Fig. 6E). Basal antennal segment L/ W 2.5 –2.6. Head length 0.44–0.45 mm................................................................. M. brusti Saether, 1989 - Median bifid tooth of mentum clearly lower than 1 st lateral teeth. Basal antennal segment L/ W 1.1 –2.4. Head length 0.13–0.47 mm............................................................................................... 10 10. Basal antennal segment L/ W 1.1. AR 0.67. Mandible with 3 inner teeth (Epler 2001: page 7.162). Procercus with 4 anal setae.............................................................. M. sp. (= Orthocladiinae genus E, Epler, 2001) ** - Not with the above combination of characters.............................................................. 11 11. AR 1.5–1.8. Head length 0.28-0.31 mm (Saether, 1989)............................... M. albolineatus (Meigen, 1818) - AR 2.0–2.2. Head length 0.39–0.47 (Saether, 1989)................................ M. eurynotus (Holmgren, 1883) ***
Published as part of Eiseman, Charles S., Namayandeh, Armin, Linden, John Van Der & Palmer, Michael W., 2023, Metriocnemus erythranthei sp. nov. and Limnophyes viribus sp. nov. (Diptera: Chironomidae: Orthocladiinae): leafminers of monkeyflowers, speedwells, and other herbaceous plants, with new observations on the ecology and habitats of other leaf-mining Chironomidae, pp. 41-68 in Zootaxa 5249 (1) on pages 56-57, DOI: 10.11646/zootaxa.5249.1.3, http://zenodo.org/record/7685232
{"references":["Epler, J. H. (2001) Identification manual for the larval Chironomidae (Diptera) of North and South Carolina. A guide to the taxonomy of the midges of the southeastern United States including Florida. North Carolina Department of Environment and Natural Resources Division of Water Quality, St. Johns River Water Management District, Palatka, Florida, iv + 530 pp.","Saether, O. A. (1989) Metriocnemus van der Wulp: a new species and a revision of species described by Meigen, Zetterstedt, Staeger, Holmgren, Lundstr ˆ m and Strenzke (Diptera: Chironomidae). Insect Systematics & Evolution, 19, 393 - 430. https: // doi. org / 10.1163 / 187631289 X 00528","Orendt, C. & Bendt, Th. (2021) Orthocladiinae sensu lato (Orthocladiinae, Prodiamesinae, Diamesinae, Podonominae, Buchonomyiinae, Telmatogetoninae) (Diptera: Chironomidae). Keys to Central European larvae with respect to macroscopic characters. DGL-Arbeitshilfe (DGL Tools) 1 - 2021. German Limnological Society (DGL) e. V., Essen, 140 pp.","Cranston, P. S. & Judd, D. D. (1987) Metriocnemus (Diptera: Chironomidae): an ecological survey and description of a new species. Journal of the New York Entomological Society, 95, 534 - 546."]}