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MARGOT P. MONSON AND RALPH W. HOLZENTHAL Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108 USA

Abstract. Males of a new species of microcaddisfly, Oxyethira (Holarctotrichia) itascae, (Trichoptera: Hydroptilidae) from the Lake Itasca region of northern Minnesota are described and illustrated. This represents the first new species of Trichoptera described from the State in nearly twenty years. Fifteen other Oxyethira species are known from the State, including 0. (Dampfitrichia) verna Ross and 0. (Oxyethira) ecornuta Morton, new records for Minnesota and the United States, respectively. Key words: Oxyethira (Holarctotrichia) itascae, caddisflies, endemic, biome.

Fifty-eight of the 280 species of Trichoptera Methods known from Minnesota are members of the Trichoptera were trapped with 15-watt D.C. family Hydroptilidae and, of these, 16 are spe black lights suspended over pans containing cies of Oxyethira Eaton. Oxyethira species have 80% ethanol and placed at water's edge. Col been reported from all the major faunal regions lections were made every two weeks from May of the world, with species records throughout to October, 1988 and 1989. Specimens were the North American continent. The larvae are cleared in 10% KOH solution (Ross 1944). Due typically encountered in standing waters or in to their small size, they were examined under lotic habitats where the current is slow. They compound and dissecting microscopes for iden commonly are located on submerged aquatic tification; illustrations were made with the aid plants, where they feed on filamentous algae of a drawing tube attachment on an Olympus and diatoms. Some species have been discov BH-2 compound microscope. Terminology for ered in faster-flowing waters on rocky, moss genitalic structures follows that of Kelley (1984). covered substrates (Marshall 1979). Larvae of Type material is deposited in the University of North American Oxyethira may be identified by Minnesota Insect Collection, St. Paul (UMSP), their exceptionally long, slender meso and me the National Museum of Natural History, tathoric legs, which are at least 2 1h times longer Smithsonian Institution, Washington, D.C. than their prolegs, a long distoventral lobe on (NMNH), and the Illinois Natural History Sur the fore tibiae, and very long antennae relative vey, Champaign, Illinois (INHS), as indicated to most other genera in the family. In the final below. instar, larvae are found within flattened, bottle shaped cases constructed entirely of silk (Wig Oxyethira (Holarctotrichia) itascae gins 1977). Monson and Holzenthal, new species Lake Itasca, headwaters of the Mississippi Fig. 2 River, is in a region of Minnesota where the northern coniferous forest, eastern deciduous Diagnosis. Oxyethira itascae is assigned to the forest, and tallgrass prairie biomes meet (Fig. subgenus Holarctotrichia Kelley because of pos 1). During 1988 and 1989, adult caddisflies were session by the males of long dorsolateral pro collected at the edge of three creeks and one cesses on segment VIII, convergent but separate small lake near Lake Itasca, as part of a study subgenital processes, and an elongate titillator on the phenology and diversity of the Trichop on the phallus (Kelley 1984). Oxyethira itascae tera of the region. During the study, a new spe bears some resemblance to 0. distinctella Mac cies of Oxyethira was discovered, which we de Lachlan and 0. araya Ross, both in the subgenus scribe here. Holarctotrichia, in the shape of segments VIII

438

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FIG. 1. The three major biomes of Minnesota and the distribution of 0. itascae, n. sp. Inset: Approximate extent of the same biomes in the Great Lakes region. and IX. In 0. araya and 0. distinctella the pos Blickle's (1979) key to Oxyethira species with terior margin of segment VIII possesses a tri slight modifications to his first couplet and the angular configuration similar to 0. itascae, and addition of a third choice. the dorsolateral processes are similar to the me 1. 8th tergite produced into a single process dial pair of processes in the new species; also, on the apicolateral margin ...... 2 in 0. araya and 0. distinctella the truncate dorsal - 8th tergite not produced into processes margin of segment IX resembles that of 0. itas on apicolateral margin ...... 14 cae (Kelley 1986). The presence of two pairs of - 8th tergite produced into two processes elongate dorsolateral processes on segment VIII on the apicolateral margin .. itascae, n. sp. distinguishes the new species from all others in the subgenus in North America. Description. Males. Length 2.8-3.0 mm. The new species can be determined using Brown in alcohol. Antennae with 25-32 seg-

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FIG. 2. Oxyethira itascae, new species, male genitalia. A. Segments VII-X, lateral; B. Segment IX, lateral; C. Segment VIII, dorsal; D. Segments VIII and IX, ventral, inset: details of inferior appendages, subgenital processes, and bilobed processes; E. Phallus, dorsal. Abbreviations: bp = bilobed process; ia = inferior ap pendage; sg = subgenital process; sl = setal lobe. ments. Genitalia as in Figure 2. Abdominal ster gent digitate apices; setal lobes and bilobed pro num VII with apicomesal process. Segment VIII cesses each with single seta. Segment X entirely roughly triangular in lateral view, with taper membranous. Phallus simple with spiralled ing posterior margin; dorsally, with squared titillator. posteromesal excavation and two pairs of elon Females and immatures. Unknown. gate dorsolateral processes: lateral pair elon Holotype. Male. Minnesota: Clearwater gate, extending beyond apex of segment IX, County: Itasca State Park, Nicollet Creek at Wil slender, acute apically, curved mesally; medial derness Drive, 47.194°N, 95.230°W, el. 1500 ft., pair about 1h length of lateral pair, setose, with 19.viii.1988, col. M. Monson (UMSP). apicomesal serrations. Segment IX roughly tri Paratypes. Minnesota: Hubbard County: angular in lateral view, retracted within VIII; LaSalle Creek at Co. Rd. 40, 47.349°N, 95.165°W, in lateral view, dorsal margin truncate, dorsal el. 1394 ft., 25.vi.1988, col. M. Monson, 29 males and lateral edges semimembranous, except for (UMSP); same, except 02. vii.1988, 2 males sclerotized region on posterior margin. Inferior (INHS); same, except 24.vii.1988, 2 males appendages fused to IX with U-shaped config (NMNH); same, except 26.vii.1988, 4 males uration in ventral view, mesally setose, tapered (UMSP); same, except 13.viii.1988, 12 males to acute apex, slightly curved mesally. Subgen (UMSP); same, except 22.viii.1988, 20 males ital plate prominent, sclerotized, with conver- (UMSP).

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Etymology. Named for Lake Itasca, the head currence in Minnesota represents a western limit waters of the Mississippi River. The name Itasca of its range, it may be a species associated pri was derived from ver(itas ca)put after the ex marily with the eastern deciduous forest, which plorer Henry R. Schoolcraft, who in 1832 found meets its western limit near the Itasca area. the lake to be the true source of the Mississippi Ross (1967) states that the ecological charac River. teristics of many caddisflies found only in small Distribution. Known from the type locality streams are a result of the complex interrela and the edge of LaSalle Creek, Hubbard Coun tionships with the terrestrial communities bor ty, in northern Minnesota; flight period is from dering them. The caddisfly faunas in these hab early June through mid September. itats are influenced by shade, leaf-fall, precipitation, the climax community, and the Discussion relationship between these variables. Correla tions have been made between caddisfly phy Oxyethira itascae is the first caddisfly to be logenetic and distributional information and the described from Minnesota since Wiggins' (1975) dispersal patterns of some plant groups with description of Chilostigma itascae (Limnephili which caddisflies have an ecological association dae) and Etnier's (1968) descriptions of Ceraclea (Ross 1967). brevis (Leptoceridae, as Athripsodes) and Polycen The state of Minnesota is at the cross roads tropus milaca (Polycentropodidae), all believed of three major biomes, the northern coniferous to be endemic species. The discovery of 0. itas forest, the eastern deciduous forest, and the tall cae at the edge of Nicollet Creek in Itasca State grass prairie, which offer habitat variety more Park is especially interesting because this is also diverse than the surrounding states (Coffin and the type locality for Chilostigma itascae, which is Pfannmuller 1988). The Itasca region in partic known only from adults and represents the sin ular is even more closely associated with this gle record for that genus outside of Scandinavia merging of biomes, because the coniferous and and Finland (Wiggins 1977). Nicollet Creek, deciduous forests intermingle in the area, grad with its silty bottom and many spring seepage ually giving way to tallgrass prairie just west areas, meanders through a wetland meadow of the Itasca region. As a result of ongoing stud surrounded by coniferous forest on its way to ies and the county biological survey of plants join Lake Itasca. and animals being conducted by the Minnesota In addition to the new species, Oxyethira ecor Department of Natural Resources, less common nuta Morton was collected during the study at species, including relicts, have been found in LaSalle Creek, also in the Itasca region of Min Minnesota. The distributions of C. itascae, 0. nesota. This creek, running from LaSalle Lake, ecornuta, 0. verna, and 0. itascae are further in has a sand and gravel bottom and empties into dication that the Lake Itasca region may rep a large pool just beyond the collection site, be resent an important confluence in the distri fore entering the Mississippi River. This col bution of the boreal and eastern deciduous forest lection represents the first record of 0. ecornuta Trichoptera faunas of North America. in the United States. This species is Holarctic, Further evidence of the significance of Min with the only other North American record from nesota's location at the junction of these biomes Ontario, Canada. It is also known from Finland is the fact that of the 280 species of caddisflies and Sweden (Kelley 1985). Given the distri recorded from Minnesota, 79, or 28%, are those butions of Chilostigma itascae, Oxyethira ecornuta, eastern species whose distribution in Minne and Oxyethira itascae, it appears that these are sota represents the western limit of their range boreal species which may have a particular ad (Monson and Holzenthal unpublished). Ex aptation to the type of habitat represented in amples include Chimarra obscura (Walker), Hy the Itasca region. droptila armata Ross, Hydatophylax argus (Harris), The collection of Oxyethira verna Ross from Lepidostoma bryanti (Banks), and Molanna try Becker and Hubbard Counties represents a new phena Betten. In addition, 30, or 11 %, are those state record for Minnesota. This Nearctic spe boreal species with the southern limit of their cies is known from many locations throughout range in North America extending to Minne the eastern half of North America. Since its oc- sota. Among these species are Hydropsyche vexa

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Ross, Polycentropus weedi Blickle and Morse, 22.viii.1988, 1 male; same, except 13.viii.1989, 4 Hagenella canadensis (Banks), and Ceraclea excisa males; same, except 30.ix.1989, 2 males; Becker (Morton). Though the analysis of the bioge County: Ottertail R. Mi 162, Hubbel Pond WMA, ography of Minnesota caddisflies is beyond the 16.viii.1982, col. N. Kirsch, 13 males. All spec scope and intention of this paper, it will be imens in UMSP. interesting to learn if further study of the dis Distribution. UNITED STATES: Alabama, tribution of plants and animals of the Itasca Florida, Illinois, Louisiana, Maine, Michigan, region reveals other organisms unique to this Minnesota, New Hampshire, New Jersey, North area or at their range limits in North America. Carolina, South Carolina, Tennessee, Texas, It is encouraging to note that many of the Wisconsin; CANADA: New Brunswick, Nova forests and their watersheds in this area, in Scotia, Ontario. cluding the type locality, are protected in State Parks, State Forests, and State Scientific and Natural Areas, the last being established to pro Acknowledgements tect and perpetuate Minnesota's rare and unique We thank Drs. Robert Kelley and Steve Harris natural resources for nature observation, edu for their advice concerning the new species. cation, and research. In addition, The Missis The University of Minnesota Insect Collection sippi Headwaters Board serves to monitor use was a valuable resource, and the unpublished and supervise research on this portion of the checklist of the Trichoptera of North America Mississippi River. north of Mexico by Dr. John Morse was also Finally, in addition to the new species and helpful. We thank the University of Minnesota new records, the following Oxyethira species Press and the State of Minnesota, Department have been recorded from Minnesota (Blickle of Natural Resources for permission to copy the 1979, Denning 1947, Etnier 1965, 1968): 0. (Ox map of Minnesota biomes ( ©, State of Minne ytrichia) aeola Ross, 0. (Oxytrichia) anabola Blic sota, Department of Natural Resources, 1988). kle, 0. (Holarctotrichia) araya Ross, 0. (Oxyethira) Appreciation is extended to Dr. Bill Miller and coercens Morton, 0. (Holarctotrichia) forcipata Roger Blahnik for reviewing the manuscript. Mosely, 0. (Holarctotrichia) michiganensis Mose This material is based upon work partially fund ly, 0. (Holarctotrichia) obtatus Denning, 0. ed by the Nongame Wildlife Program of the (Dampfitrichia) pallida (Banks), 0. (Oxyethira) riv Minnesota Department of Natural Resources and icola Blickle and Morse, 0. (Oxyethira) rossi Blic the Minnesota chapter of The Nature Conser kle and Morse, 0. (Holarctotrichia) serrata Ross, vancy. We gratefully acknowledge this support. 0. (Oxyethira) sida Blickle and Morse, and 0. This is technical contribution No. 20,407, Sci (Oxyethira) zeronia Ross. entific Journal Series, Minnesota Agricultural New state records for Oxyethira ecornuta and Experiment Station, St. Paul, Minnesota. Oxyethira verna from Minnesota are as follows:

Oxyethira (Oxyethira) ecornuta Morton 1893: 79- Literature Cited 80, Pl. VI, figs. 1-5, male, (Zoologiska Mu seum, Helsinki, Finland). BLICKLE, R. L. 1979. Hydroptilidae (Trichoptera) of America north of Mexico. Station Bulletin 509. New record. MINNESOTA: Hubbard Coun New Hampshire Agricultural Experiment Sta ty: LaSalle Cr. at Co. Rd. 40, 47.349°N, 95.165°W, tion, University of New Hampshire. 23.vii.1988, el. 1394 ft., col. M. Monson, 1 male COFFIN, B., AND L. PFANNMULLER (editors). 1988. (UMSP). Minnesota's Endangered Flora and Fauna. Uni Distribution. UNITED STATES: Minnesota; versity of Minnesota Press, Minneapolis. CANADA: Ontario; FINLAND; SWEDEN. DENNING, D. G. 1947. New species and records of North American Hydroptilidae (Trichoptera). Oxyethira (Dampfitrichia) verna Ross, 1938: 118- Psyche 54:170-177. 119, fig. 27, male, (INHS). ETNIER, D. A. 1965. An annotated list of the Tri choptera of Minnesota, with description of a new New records. MINNESOTA: Hubbard Coun species. Entomological News 76:141-152. ty: LaSalle Cr. at Co. Rd. 40, 47.349°N, 95.165°W, ETNIER, D. A. 1968. Range extensions of Trichoptera el. 1394 ft., 25.vi.1988, col. M. Monson, 1 male; into Minnesota, with descriptions of two new same, except 13.viii.1988, 4 males; same, except species. Entomological News 79:188-192.

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KELLEY, R. W. 1984. Phylogeny, morphology and Illinois species. Bulletin of the Illinois Natural classification of the micro-caddisfly genus Oxy History Survey 21:101-183. ethira Eaton (Trichoptera:Hydroptilidae). Trans Ross, H. H. 1944. The caddis flies, or Trichoptera, actions of the American Entomological Society of Illinois. Bulletin of the Illinois Natural History 110:435-463. Survey 23:1-326. KELLEY, R. W. 1985. Revision of the micro-caddisfly Ross, H. H. 1965. Pleistocene events and insects. genus Oxyethira (Trichoptera:Hydroptilidae). Part Pages 583-596 in H. E. Wright and D. G. Frey II: subgenus Oxyethira. Transactions of the Amer (editors). The Quaternary of the United States. ican Entomological Society 111:223-253. Princeton University Press, Princeton. KELLEY, R. W. 1986. Revision of the micro-caddisfly Ross, H. H. 1967. The evolution and past dispersal genus Oxyethira (Trichoptera:Hydroptilidae). Part of the Trichoptera. Annual Review of Entomol III: subgenus Holarctotrichia. Proceedings of the ogy 12:169-206. Entomological Society of Washington 88:777-785. WIGGINS, G. B. 1975. Contributions to the system MARSHALL, J.E. 1979. A review of the genera of the atics of the caddisfly family Limnephilidae (Tri Hydroptilidae (Trichoptera). Bulletin of the Brit choptera). II. The Canadian Entomologist 107:325- ish Museum (Natural History). Entomology se 336. ries 39:135-239. WIGGINS, G. B. 1977. Larvae of the North American MORTON, K. J. 1893. Notes on Hydroptilidae be caddisfly genera (Trichoptera). University of To longing to the European fauna, with descriptions ronto Press, Toronto. of new species. The Transactions of the Ento mological Society of London IV: 75-84. Received: 6 April 1993 Ross, H. H. 1938. Descriptions of Nearctic caddis Accepted: 17 September 1993 flies (Trichoptera) with special reference to the

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