Mayflies (Ephemeroptera) of the Great Plains. I: Nebraska

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1 Transactions of the American Entomological Society 127(1): 5-29, 2001 Mayflies (Ephemeroptera) of the Great Plains. I: Nebraska W. P. McCafferty Department of Entomology, Purdue University, West Lafayette, IN Tom H. Klubertanz Department of Biological Sciences, University of Wisconsin - Rock County, Janesville, WI53546 R. P. Randolph Department of Entomology, Purdue University, West Lafayette, IN Arwin V. Provonsha Department of Entomology, Purdue University, West Lafayette, IN Division H. R. Lawson of Science and Mathematics, Chadron State College, Chadron, NE B. C. Kondratieff Department of Bioagricultural Sciences and Pest Management, Colorado State Univ., Fort Collins, CO abstract A total of 13 families, 39 genera, and 81 species of are Ephemeroptera reported from the state of Nebraska, including the first published state records for two families, 13 genera, and 38 species. Also provided are 335 new records for 65 of the are now species. Mayflies known from 60 of the 93 Nebraska counties and from all areas drainage represented in the state. Most species of the Nebraska fauna are common relatively in North America. Notable exceptions include Apobaetis lakota McCafferty, Brachycercus edmundsi Sold?n, B. nasutus Sold?n, Cercobrachys serpentis Sold?n, Leptophlebiagravastella (Eaton), and Paraleptophlebia gregalis (Eaton). Much of the mayfly fauna is psammophilous, being typical of sand-bottomed streams, which are predomi nate throughout much of the state. The generally mixed North American geographic affinities of the Nebraska fauna are tabulated, and several species significantly demonstrate their eastern, western, or northern range limits in this north-central plains state.

2 6 GREAT PLAINS MAYFLIES BACKGROUND AND DISCUSSION Nebraska was one of several North American states indicated by McCafferty (2000a) as not having been studied to any significant extent with respect to its Ephemeroptera fauna. Study of the Nebraska mayflies was deemed important because of the central geographic position of the state, its relatively large size (77,227 square miles), and its extensive sand bottomed streams and rivers. Thus, the Nebraska fauna could yield important data for understanding transcontinental ranges of the North American fauna as well providing a better understanding of the poorly known psammophilous mayfly fauna (e.g., see McCafferty 1991). Ratcliffe (1990) provided an excellent physiographic review of this state from the perspective of insect habitat. Nebraska is primarily prairie with six different short and tall grassland types found throughout most of the state, although much of the prairie is now in cultivation. Pine ridges to the extent of 5,340' elevation occur in the far western portion of the state, and deciduous forest as low as 835' elevation may be found in the Missouri in Valley the extreme southeast. In the western two-thirds of the state are the Nebraska Sand Hills (19,300 square miles), the largest sand dune area in the Western Hemisphere. Streams range from low flow springs with moderate gradient and mixed substrates (e.g., Chadron Creek) to moderately large streams with predominately silt and sand bottoms (e.g., Elkhorn River) to long, meandering, low gradient streams, often ribboned due to considerable draw down for agricultural and seasonal low precipitation, that typically exhibit clean shifting sand substrates (e.g., Niobrara River) to the large Missouri River. Previous to this study, published reports of mayflies from Nebraska with associated record data included only 28 species (Traver 1935, Spieth 1941, Hamilton 1959, Swanson 1967, McCafferty 1975, Bednarik and McCafferty 1979, Kondratieff and Voshell 1984, Moul 1984, Pescador 1985, Provonsha and McCafferty 1985, McCafferty and Waltz 1986, Darrow and Pruess 1989, Provonsha 1990, Harris et al. 1999, Klubertanz and Jones 1999, McCafferty 2000b, Wiersema and McCafferty 2000). Five unpublished theses (Hamilton 1952, Pesek 1974, Carnevalo 1981, Decker 1981, Angle 1987) provided data associated with mayflies in Nebraska. Any reports of species in Nebraska contained in those studies are noted in the present study with respect to those that could be verified with additional records given herein or elsewhere or those that should have been identified with confidence at the time considering the state of taxonomic knowledge and available aids. diagnostic Voucher materials from the Carnevalo and Decker theses, if existent, were not made avail able to us upon request; however, AVP verified several of the species involved at the time of the studies. Several vouchers from the Hamilton (1952) study that had been initially deposited at the University of Utah and now reside at PERC were examined by WPM. Eleven of the 81 species reported herein remain based on entirely unpublished theses or abstracts thereof (Carnevalo and Lunt 1982, Decker and Lunt 1982). Our review of previous reports and study of large collections of Nebraska Ephemeroptera variously accumulated us by for the past

3 W. P. MCCAFFERTY ET AL. 7 nearly 25 years, have indicated the occurrence of 13 families, 39 genera, and 81 in the state. Reviewed and new data are mayfly species presented in the text, and Table 1 is as a provided summary indication of the geographic affinities of the Nebraska species. From Table 1, it can be seen that several species find their western, eastern, northern, or less com monly southern distribution limits in Nebraska, and that Nebraska is a clearly transitional area with to respect the eastern and western North American fauna. Of considerable interest is the fact that certain otherwise southwestern species have been found in the Pine Ridge area of far western Nebraska, for example, Baetis magnus McCafferty and Waltz and Caenis bajaensis Allen and Murvosh. Some western widespread species, such as Heptagenia elegantula (Eaton) are also common throughout Ne braska but remain unknown east of there. Several eastern and mid western species apparently find western limits in eastern Nebraska, for example, Tricorythodes allectus (Needham) and Stenonemafemoratum (Say), although some of these, such as the latter, occur somewhat farther west in Canada (McCafferty and Randolph 1998). Nebraska serves as a bridge between western and eastern populations for certain species such as Ephemerella inermis Eaton and Stenonema terminatum (Walsh). None of the 81 mayfly species are endemic to Nebraska. The vast majority of Nebraska mayflies are common species through out their ranges in North America. In particular, however, Nebraska has a relatively rich fauna of caenid mayflies (both Caeninae and Brachycercinae), long-clawed Baetidae, Pseudironidae, and Homoeoneuria - (Oligoneuriidae) all groupings commonly associated with sand sub strates. Generally poorly known and infrequently taken mayflies found in Nebraska include Apobaetis lakota McCafferty, Camelohaetidius waltzi McCafferty, Brachycercus edmundsi Sold?n, B. nasutus Sold?n, B. prudens (McDunnough), Caenis youngi Roemhild, Cercobrachys serpentis Sold?n, Homoeoneuria ammophila (Spieth), Leptophlebia gravastella (Eaton), and Paraleptophlebia gregalis (Eaton). The first two species have only recently been discovered, are small and difficult to collect, and thus it is premature to estimate their or potential rarity environmental status. Species of Brachycercus and are Cercobrachys poorly understood, and thus many collected are not specimens identified to species, and no valid estimation of or rarity environmental concern can be made for these species at this time. In addition, the sand-silt habitats that Brachycercinae are found in are often not sampled adequately. Recent collections of C. youngi by WPM and AVP outside Nebraska would indicate that this species is much more common than previously thought. Homoeoneuria is more probably common than reports would indicate because its psammophilous habitat has not been adequately sampled. The taxonomic status of L. gravastella must be validated before estimates of rarity are assigned to it. Also, future studies of western species of the genus Paraleptophlebia should reveal the true commonness of P. a gregalis, species that notably had not been as far east as Nebraska. previously reported Historical and new faunistic data are reported below with no further comment. Presentation is alphabetical by family, genus, and species. All

4 8 GREAT PLAINS MAYFLIES previous reports, whether or not and whether or published complete not, are given under Previous reports. state and records are in given full. Only the first name of any collectors are given per record (abbreviated in the case of present authors). If a species has previously been for a reported, additional records from that are not given here. names County appear in all capital letters for easier tracking. For reference, the location of counties with stream are along key systems shown on the Nebraska state map in 1. Data are given Fig. abbreviated as much as to conserve possible printed space. The materials for which new record data are are in reported mostly deposited the Purdue Entomo logical Research Collection (West Lafayette, Indiana). However, material associated with collectors names including Klubertanz (THK), Clopton, or Sorgenfrei are deposited in the private collection of THK (Janseville, Wisconsin), except for material new state contributing records, which are also deposited in PERC. Those with collectors name including Kondratieff (BCK), Harris, or Opler are deposited at the C. P. Gillette Museum of Arthropod Diversity, Colorado State University (Fort Collins, Colorado). FAUNISTIC DATA BAETIDAE Acentrella Previous indicated ampia Traver reports.?carnevalo (Niobrara R). and Lunt (1982) as Baetis: no Acentrella insignificans (McDunnough) Previous reports.?hamilton (1952) as Baetis bicaudatus: CHERRY (Niobrara R). Harris et al. (1999): SIOUX (Niobrara R). records.? BLAINE: N Loup R, Co Rd 1, VI , THK; BROWN: Niobrara R, Hwy 183, S Springview, VI , THK; DAWES: Niobrara R, below Box Butte Dam, VI , WPM; Niobrara R, VIII 10,VIII ; White R, Rt 385 bridge, VII , HRL; HALL: Platte R, 2 mi N Doniphan, IX , Sorgenfrei; KEITH: larvae, Otter Cr, St Hwy 92, V , BCK; KEYA PAHA: Niobrara R, Hwy 183, S Springview, VI , THK; SHERIDAN: Niobrara R, Gordon, VII 11,VIII , HRL. Acentrella p?rvula (McDunnough) Previous reports.?carnevalo (1981) as Pseudocloeon: CHERRY (Minnechaduza R, Snake R); SHERIDAN (Niobrara R). Decker (1981) as Pseudocloeon: DUNDY (Republican R); FRONTIER (Medicine Cr); FURNAS (Republican R); HAYES (Frenchman R); WEBSTER (Republican R). records.? BLAINE: Goose Cr, Co Rd 7, S Koshopah; N Loup R, Co Rd between Purdum & Brewster, VI , THK; BROWN: Plum Cr, Hwy 20 W Johnstown, VI , BCK; DAWES: Niobrara R, below Box Butte Dam, VI , WPM; White R, Crawford, VII ; White R, Ard Rd, VI , HRL; KEITH: Otter Cr, St Hwy 92, V , BCK; GARDEN: Blue Cr, vi , BCK; LOUP: Calamus R, Hwy 183,

5 W. P. MCCAFFERTY ET AL /56/49N 99/23/09W, VI , WPM; PAWNEE: N Frk Big Nemaha R, St Rd 4,1 mi E Table Rock, VIII , THK; RICHARDSON: Muddy Cr, Hwy 73,1 mi W Verd?n, IX ; S Frk Big Nemaha R, 8 mi SW Humboldt, V , THK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; Hay Springs Cr, V , HRL; THOMAS: Dismal R, 13.9 mi S Thedford; Middle Loup R, entrance Neb Nat For, 1 mi W Halsey, VI , THK; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Acentrella t?rbida (McDunnough) Previous reports.?carnevalo (1981), Carnevalo and Lunt (1982) as Pseudocloeon Carolina (Banks): KEY A PAH A (Keya Paha R). records.? BROWN: Pine Long Cr, vi , BCK. Acerpenna pygmaea (Hagen) Previous reports.?carnevalo (1981) as Baetis: CHERRY (Minnechaduza R); ROCK (Ash Cr). records.? BLAINE: N Loup R, Co Rd 1, VI , THK; DAWES: Niobrara R, V ; HOLT: Elkhorn R, 1 mi S Hwy 20,5 mi SE Stuart, VI ; S Frk Elkhorn R, Hwy 95, VI , THK; LO GAN: S Loup R, Hwy 83,1.3 mi N Stapleton, VI , THK; PAWNEE: N Frk Big Nemaha R, 1 mi E Table Rock, Hwy 4, IX , THK. Apobaetis lakota McCafferty Previous report s.? McCafferty (2000b): SALINE (Big Blue R). Baetis flavistriga McDunnough Previous reports.?carnevalo (1981) as B. levitans: BOX BUTTE (Niobrara R). Carnevalo (1981) as B. quebecensis: CHERRY (Niobrara R); KEYA PAHA (Keya Paha R); KNOX (Niobrara R). Decker (1981) as B. levitans: HITCHCOCK (Republican R). Decker (1981) as B. quebecensis: FURNAS (Muddy Cr, Republican R); HAYES (Red Willow Cr). Baetis intercalaris McDunnough Previous reports.?decker (1981): FURNAS (Muddy Cr; Republican R); HAYES (Red Willow Cr). Klubertanz and Jones (1999): RICHARDSON (S Frk Big Nemaha R). records.? CASS: Platte R, Louisville L Prk, VII , THK; DAWES: White R, Crawford, VII ; White R, N Chadron, VIII , HRL; GAGE: Big Indian Cr, Hwy 77,1 mi S Wymore, V , THK; JOHNSON: nr Elk Cr, VIII , THK; NEMAHA: Honey Cr, St Rd 67, 2 mi SE Peru, VI ; floodwaters Missouri R, Peru, VII ; Missouri R, Brownville, VIII , THK; PAWNEE: N Frk Big Nemaha R, St Rd 4,1 mi E Table Rock, VIII ; Taylor Br, St Rds 4/ 65, Table Rock, V , THK; SIOUX: Agate Cr, VIII ; Niobrara R, "Agate", VI , HRL; Niobrara R, Agate Fossil Beds, VIII , BCK; WASHINGTON: Brown Cr, Co Rd 26,41/30/33N 96/22/44W, VI , WPM.

6 10 GREAT PLAINS MAYFLIES Baetis magnus McCafferty and Waltz Previous reports.?mccafferty and Waltz (1986): DAWES (Chadron Cr, Rapid Cr, Squaw Cr, W Ash Cr); SIOUX (Sowbelly Canyon Cr). BCK. records.? CHERRY: trib. Niobrara R, Hwy 61, vi , Baetis tricaudatus Dodds Previous reports.?decker (1981) as B. vagans: FRANKLIN (Cotton wood Cr); FURNAS (Republican R); HAYES (Frenchman R); HITCHCOCK (Republican R); Carnevalo (1981) as B. vagans: BOX BUTTE (Niobrara R); BROWN (Long Pine Cr); CHERRY (Niobrara R); HOLT (N Br Verdigris Cr); KNOX (Niobrara R); ROCK (Ash Cr). records.?cass: Cr nr falls, Platte R Prk, VII , THK; DAWES: Box Butte overflow pond; Chadron St Coll Pond; Niobrara R, below Box Butte Dam, VI ; Niobrara R, 2 mi E Marsland, VI ; Chadron Cr, Chadron St Prk, VI , VI , WPM; White R, Hwy 20, II , BCK; Bordeaux Cr, V-25,VI ; W Ash Cr, VII 26,VIII ; Pepper Cr, VII-25,VIII ; Chadron Cr, V-9,VI 13,VII ; Niobrara R, V ; Niobrara R, below Box Butte Res at light, VIII ; White R, VI-l,7,ll,VII-2,6,20,VIII-15,17,IX ; Squaw Cr, VI-25,VII , HRL; Squaw Cr, rd 707 SW Crawford, VII , BCK; Dead Horse Cr, Hwy 20, III-l ; White Clay Cr; HALL: Platte R, St Rd 11/1-80, VI , AVP; KEITH: Otter Cr, St Hwy 92, V , BCK; KEYA PAHA: Niobrara R, Hwy 183, S Springview, VI , THK; LOGAN: S Loup R, Rt 83, V , HRL; NEMAHA: floodwaters Missouri R, Peru, VII ; Honey Cr, St Rd 67, 2 mi SE Peru, X , THK; RICHARDSON: Muddy Cr, Hwy 73, 1 mi W Verd?n, V , THK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; Niobrara R, VIII ; Beaver Cr, VI-22,VII , HRL; SIOUX: Niobrara R, Agate Springs Ranch, St Rd 29; Monroe Canyon Cr, Gilbert Baker St Wildl Ref Campsite, VI , WPM; Niobrara R, "Agate", VI ; Soldier Cr, V-13,VI-ll,VII-6,20,VIII-15,IX ; at Agate light, VII ; Spring Cr at light, VI ; Hat Cr, IV-2,V-14,VI ; Sowbelly Canyon Cr, VI-5,VII , HRL. Callibaetis ferrugineus (Walsh) Previous reports.?hamilton (1952): SCOTTS BLUFF (Mitchell). records.? DAWES: Chadron Cr, VII , VII (at light); Pepper Cr, VI-14,VII , V-26,VI ; W Ash Cr, X , HRL; GARFIELD: pond E Burwell, St Rd 91, 41/47/14N 99/07/ 13W, VI , WPM; SIOUX: Sowbelly Canyon Cr, VIII , HRL. Callibaetis fluctuans (Walsh) Previous reports.? Hamilton (1952): LANCASTER (Lincoln); MADI SON (Norfolk); PIERCE (Plainview); PLATTE (Columbus); SCOTTS BLUFF (Mitchell, Scottsbluff). Hamilton (1952) as C. montanus: CASS (Plattsmouth Pond); SCOTTS BLUFF (Mitchell). records.? BROWN: marsh at Co Rd 7, E Willow L St Wildl Mgmt Area, VI , THK; BUFFALO: Kearney, IX , Koss;

7 W. P. MCCAFFERTY ET AL. 11 DAWES: Box Butte Res, overflow pond, VI , WPM; Chadron St Coll at light, IX ; W Ash Cr, VII ; Chadron at light, VIII , HRL; HALL: pond, Mormon Is Rec Area, IV , WPM; KEITH: Neven's Pond, VI , Clopton; LOUP: Calamus R, Hwy 183,41 /56/ 49N 99/23/09W, VI , WPM; MADISON: Norfolk, VIII ; NEMAHA: Peru St Coll at light, VIII , THK; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Callibaetis pallidus Banks Previous reports.?hamilton (1952) as C. semicostatus: LANCASTER (Lincoln pond). records.? KEITH: Neven's Pond, VI , Clopton; NEMAHA: Auburn at light, VI ; Peru St Coll at light, VIII , THK. Callibaetis pictus (Eaton) state records.?-dawes: larvae, Chadron Cr, VI , HRL; KEITH: larvae, Neven's Pond, VI , Clopton; NEMAHA: larvae, Honey Cr, St Rd 67, 2 mi S Peru, X , THK. Camelobaetidius variabilis Wiersema state records.?knox: larvae, N Br Verdigre Cr, NW, SW, Sec. 33, T31N, R08W, VII , D. Schumacher. Camelobaetidius waltzi McCafferty Previous reports.?klubertanz and Jones (1999): PAWNEE (N Frk Big Nemaha R); RICHARDSON (Muddy Cr, S Frk Big Nemaha R). Camelobaetidius warreni (Traver and Edmunds) state records.?blaine: larvae, N Loup R, Co Rd between Purdum & Brewster, VI , THK; N Loup R, Co Rd 1,12 mi NW Brewster, VI , BCK; BROWN: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; CHERRY: larvae, Niobrara R, Hwy 61, VI , BCK; GARDEN: larvae, Blue Cr. vi , BCK; KEYA PAHA: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; LOUP: larvae, Calamus R, Hwy 183,41/56/49N 99/23/09W, VI , WPM; SHERIDAN: larvae: Niobrara R, St Rd 27, VI , WPM; Niobrara R, Peters, VII-18, ; Niobrara R, Gordon, VII , HRL; THOMAS: larvae, Mid Loup R, entrance Neb Nat For, 1 mi W Halsey, VI , THK. Centroptilum album McDunnough Previous reports.?hamilton (1952) as C. walshi: PLATTE (Columbus); SEWARD (Seward). Carnevalo (1981): KNOX (Niobrara R). Decker (1981): DUNDY (Republican R); HAYES (Frenchman R); HITCHCOCK (French man R, Republican R). records.? RICHARDSON: S Frk Big Nemaha R, Hwy 8,8 mi SW Humboldt, at light, VII , THK.

8 12 GREAT PLAINS MAYFLIES Centroptilum bifurcatum McDunnough state records: BROWN: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; Plum Cr, Hwy 20 W Johnstown, VI , BCK; CHERRY: larvae & adults, Snake R, Rt 61, VI ; larvae, Niobrara R, Hwy 61, VI , BCK; GARDEN: larvae, Blue Cr, Rackett Rd, V , BCK; HALL: larvae, Platte R, St Rd 11/1-80, IV , WPM; KEYA PAHA: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; LOUP: larvae, Calamus R, Hwy 183,41/56/49N 99/23/09W, VI , WPM; SIOUX: larvae, Niobrara R, Agate Springs Ranch, St Rd 29, VI , WPM; THOMAS: larvae, Dismal R, 13.9 mi S Thedford, VI , THK; WHEELER: larvae, Cedar R, St Rd 70/91E Ericson, 41 /47/ 00N 98/41/53W, VI , WPM. convexum Centroptilum Ide Previous reports.?carnevalo (1981): BROWN (Niobrara R); CHERRY (Minnechaduza R, Niobrara R); KNOX (Niobrara R). Decker (1981): DUNDY (Republican R, S Frk Republican R); HAYES (Frenchman R); HITCHCOCK (Republican R); SHERIDAN (Niobrara R). Diphetor hageni (Eaton) Previous reports.?carnevalo (1981), Carnevalo and Lunt (1982) as Baetis: CHERRY (Minnechaduza R); KNOX (N Br Verdigris Cr). Fallceon quilleri (Dodds) Previous reports.?klubertanz and Jones (1999): PAWNEE (N Frk Big Nemaha R); PLATTE (Columbus); RICHARDSON (S Frk Big Nemaha R). Harris et al. (1999): SIOUX (Niobrara R). records.? BLAINE: Dismal R, St Rd 2, S Dunning; N Loup R, Co Rd between Purdum & Brewster, VI , THK; N Loup R, Co Rd 1,12 mi NW Brewster, VI , BCK; BROWN: Niobrara R, Hwy 183, S Springview, VI , THK; CASS: Platte R, Louisville L Prk, VII , THK; CHERRY: Niobrara R, Hwy 61; Leander Cr, Hwy 61VI , BCK; DAWES: Niobrara R, below Box Butte Dam, VI , WPM; Pepper Cr, V-26,VII ; Dead Horse Cr; E Ash Cr, VII ; Chadron Cr, IV-4,25,V-31,VII-19,VIII ; Bordeaux Cr, VII 30,VIII , HRL; Squaw Cr, Rd 707 SW Crawford, VII , BCK; DODGE: Elkhorn R, St Rd 91,41/32/21N 96/27/15W, VI , WPM; FURNAS: Republican R at Oxford, VIII , AVP; GAGE: Plum Cr, 0.8 mi S St Rd 8 to Oketo, V ; Turkey Cr, 4 mi N Holmesville, VII , THK; HOLT: Elkhorn R, 1 mi S Hwy 20, 5 mi SE Stuart, VI , THK; JOHNSON: nr Elk Cr, VIII , THK; KEYA PAHA: Niobrara R, Hwy 183, S Springview, VI , THK; LOGAN: S Loup R, Hwy 83,1.3 mi S Thedford, VI , BCK; NEMAHA: Floodwaters Missouri R, Peru, VII ; Honey Cr, St Rd 67,2 mi S Peru, X ; Missouri R, Brownville, VIII , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Prk, VII , THK; SHERIDAN: Beaver Cr, VI 8,21,25,VII-3,18,VIII ; Niobrara R, VIII , HRL; SIOUX: Sol dier Cr, VII , VIII ; White R, VII , IX , HRL; Niobrara R, Agate Fossil Beds, VIII , BCK; THOMAS: Mid Loup

9 W. P. MCCAFFERTY ET AL. 13 R, Entrance Neb Nat For, 1 mi W Halsey, VI , THK; WHEELER: Cedar R, St Rd 70/91 E Ericson, VI , WPM. Paracloeodes minutus (Daggy) Previous reports.?carnevalo (1981): CHERRY (Niobrara R); SHERIDAN (Niobrara R). Decker (1981): DUNDY (Republican R, S Frk Republican R); FRANKLIN (Turkey Cr); FURNAS (Republican R); HITCHCOCK (Republican R); RED WILLOW (Republican R). records.? BLAINE: N Loup R, Co Rd 1, VI , THK; BROWN: Niobrara R, Hwy 183, S Springview, VI , THK; BUF FALO: Platte R, Kearney, VIII , AVP; GARDEN: Blue Cr, vi , BCK; JOHNSON: nr Elk Cr, VIII , THK; KEYA PAHA: Niobrara R, Hwy 183, S Springview, VI , THK; NEMAHA: Honey Cr, St Rd 67,2 mi S Peru, X , THK; PAWNEE: N Frk Big Nemaha R, 4 mi N Table Rock, VIII ; N Frk Big Nemaha R, 1 mi E Table Rock, Hwy 4, IX , THK; RICHARDSON: Muddy Cr, Hwy 73,1 mi W Verd?n, V , THK. Plauditus dubius (Walsh) Previous reports.?hamilton (1952) as Pseudocloeon: SEW ARD (Seward). Carnevalo (1981) as Pseudocloeon: BOX BUTTE (Niobrara R); BROWN (Long Pine Cr); CHERRY (Minnechaduza R); HOLT (N Br Verdigris Cr); KNOX (Niobrara R); SHERIDAN (Niobrara R). Plauditus punctiventris (McDunnough) Previous reports.?carnevalo (1981) as Pseudocloeon or P. myrsum: BROWN (Long Pine Cr); CHERRY (Minnechaduza R); HOLT (N Br Verdigris Cr); KEYA PAHA (Keya Paha R); KNOX (Niobrara R, N Br Verdigris Cr); SHERIDAN (Niobrara R). records.? DAWES: Niobrara R, below Box Butte Dam, VI , WPM; GARDEN: Blue Cr, vi , BCK; LOGAN: S Loup R, Hwy 83,1.3 mi N Stapleton, VI , BCK; LOUP: Calamus R, Hwy 183, 41/56/49N 99/23/09W, VI , WPM; RICHARDSON: Muddy Cr, Hwy 73,1 mi W Verd?n, V ; S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, V , THK; SIOUX: Niobrara R, Agate Springs Ranch, St Rd 29, VI , WPM; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Procloeon rufostrigatum (McDunnough) state records: DODGE: larvae, Elkhorn R, St Rd 91,41/32/21N 96/27/15W, VI , WPM; RICHARDSON: larvae, S Frk Big Nemaha R, St Rd 8, 8 mi SW Humboldt, VIII , THK. Pseudocloeon dardanum (McDunnough) Previous reports.?-harris et al. (1999): SIOUX (Niobrara R). records.? BLAINE: Dismal R, St Rd 2, S Dunning, VI , THK; Dismal R, Co Rd off Hwy 83,13.9 mi S Thedford, VI , BCK; CASS: Platte R, Louisville L Prk, VII , THK; DODGE: Elkhorn R, StRd 91,41 /32/21N 96/27/ 15W, VI , WPM; DOUGLAS: Missouri

10 14 GREAT PLAINS MAYFLIES R, Dodge Prk, Omaha, VI , THK; GAGE: Big Blue R, bridge E Hoag, VI , THK; GREELEY: Cedar R, St Rd 91,41 /41 /50N 98/25/ 23W, VI , WPM; LOUP: Calamus R, Hwy 183,41/56/49N 99/23/ 09W, VI , WPM; NEMAHA: Missouri R, Peru, VI , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, V , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Prk, VII , THK; THOMAS: Dismal R, 13.9 mi S Thedford, VI , THK; VAL LEY: Middle Loup R, Arcadia, VI , BCK; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Pseudocloeon frondale (McDunnough) Previous reports.?hamilton (1952) as Baetis australis: HOLT (Cache Cr). Pseudocloeon longipalpus (Morihara and McCafferty) state records: CASS: larvae, Platte R, Louisville L Prk, VII , THK; NEMAHA: larvae: Missouri R, Brownville, VII ; flood waters Missouri R, Peru, VII , THK; RICHARDSON: larvae, S Frk Big Nemaha R, St Rd 8, 8 mi SW Humboldt, V , THK. Pseudocloeon propinquum (Walsh) state records: BLAINE: larvae: Goose Cr, St Rd 7, S Koshopah; N Loup R, Co Rd 1, VI , THK; BROWN: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; Plum Cr, Hwy 20 W Johnston, VI , BCK; BUFFALO: adults, Kearney, IX , Koss; CHERRY: lar vae, Snake R, S Hwy 61, VI ; Dry Cr, Merriman; Niobrara R, Hwy 61; Leander Cr, Hwy 61, VI , BCK; DAWES: adults: Niobrara R, below Box Butte Dam, VI ; Niobrara R, 2 mi E Marsland, VI ; larvae: Chadron Cr,.5 mi S Chadron St Prk, VI , WPM; FURNAS: adults, Republican R, Oxford R channel, VIII AVP; GARDEN: Blue Cr, vi , BCK; HOLT: larvae, Elkhorn R, 1 mi S of Hwy 20,5 mi SE Stuart, VI , THK; KEYA PAHA: larvae, Niobrara R, Hwy 183, S Springview, VI , THK; LOGAN: larvae, S Loup R, Hwy 83,1.3 mi N Stapleton, VI , THK; LOUP: larvae, Calamus R, Hwy 183,41 /56/49N 99/23/09W, VI , WPM; SHERIDAN: larvae: Niobrara R, St Rd 27, VI , WPM; Niobrara R, V-29,VIII ; Pine Cr, Hwy 250, HRL; SIOUX: adults, Niobrara R, Agate Springs Ranch, St Rd 29, VI , WPM; larvae, Niobrara R, VI , HRL; THO MAS: larvae, Dismal R, 13.9 mi S Thedford; Mid Loup R, entrance Neb Nat For, 1 mi W Halsey, VI , THK; WHEELER: larvae, Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. BAETISCIDAE Baetisca lacustris McDunnough Previous reports.?carnevalo (1981) as B. bajkovi: KEYA PAHA (Keya Paha R).

11 W. P. MCCAFFERTY ET AL. 15 CAENIDAE Amercaenis ridens (McDunnough) Previous reports.?hamilton (1952) as Caenis: DAWSON (Cozad). Decker (1981) as Caenis: HITCHCOCK (Republican R). Provonsha and McCafferty (1985): CHERRY (Niobrara R); FURNAS (Republican R); WEBSTER (Republican R); RED WILLOW (Republican R). records.? BUFFALO: Kearney at light, VIII , AVP; CASS: Platte R, Louisville L Prk, VII , THK; NEMAHA: Auburn at light, VII ; Floodwaters Missouri R, Peru, VII , THK; PLATTE: Platte R, S Duncan, VIII , BCK; SARPY: Platte R, St Rd 31, 1 mi E Schramm Prk, VII , THK. Brachycercus edmundsi Sold?n state records: BLAINE: larvae, Goose Cr, Co Rd 7 Koshopah, VI , THK; HALL: larvae, Platte R, St Rd 11/1-80, IV ; WPM; SHERIDAN: larvae: Niobrara R, St Rd 27, VI , WPM; Niobrara R, Gordon, VIII ; Niobrara R, V-29,VI-8,VIII , HRL; WHEELER: larvae, Cedar R, St Rd 70/90 E Ericson, 41/47/00N, 98/41/ 53W, VI , WPM. Brachycercus nasutus Sold?n state records: SHERIDAN: larvae: Niobrara R, S Gordon, VII ; Niobrara R, Gordon, VII , HRL. Brachycercus prudens (McDunnough) Previous reports.?hamilton (1952): PLATTE (Columbus). records.? HAYES: Frenchman R, Hwy 6,4.7 mi E Waunita, VI , BCK. Caenis arnica Hagen Previous reports.?hamilton (1952): DAKOTA (South Sioux City). Hamilton (1952) as C. simulans: BOX BUTTE (Alliance); GRANT (Hyannis); PIERCE (Pierce); SIOUX (Univ L). Provonsha (1990): CASS (Weeping Water Cr Impoundment); CHERRY (Sparks); DAWES (Niobrara R); DOUGLAS (Papio Cr); HOLT (Papio Cr); PAWNEE (Johnson Cr). records.? BROWN: Keller Prk St Rec Area at light, Hwy 183, 9.6 mi NE Ainsworth, VI , THK; FURNAS: Oxford at light, VIII , AVP; GARFIELD: pond E Burwell, St Rd 91,41 /47/14N 99/ 07/13W, VI , WPM; HAYES: Frenchman R, Hwy 6, 4.7 mi E Waunita, VI , BCK. Caenis bajaensis Allen and Murvosh Previous reports.?provonsha (1990): DAWES (Bordeaux Cr, Chadron Cr, Chadron St Coll Pond, Sowbelly Cr); SHERIDAN (Beaver Cr); SIOUX (White R). Caenis hilaris (Say) Previous reports.?hamilton (1952): PLATTE (Columbus); RED WIL

12 16 GREAT PLAINS MAYFLIES LOW (McCook). Provonsha (1990): CHERRY; FURNAS (Republican R). records.? BLAINE: Goose Cr, St Rd 7, S Koshopah; N Loup R, Co Rd between Purdum & Brewster, VI , THK; N Loup R, Co Rd 1,12 mi NW Brewster, VI , BCK; BROWN: Niobrara R, Hwy 183, S Springview, VI , THK; DAWES: White R, VIII , HRL; KEYA PAHA: Niobrara R, Hwy 183, S Springview, VI , THK; NEMAHA: floodwaters Missouri R, Peru, VII ; Peru St Coll at light, Peru, VII , THK; PAWNEE: N Frk Big Nemaha R, 4 mi N Table Rock, VIII , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, VII , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Pk, VII , THK; SHERIDAN: Niobrara R, S Gordon, VII ; Niobrara R, VIII , HRL; THOMAS: Dismal R, 13.9 mi S Thedford; Mid Loup R, Entrance Neb Nat For, 1 mi W Halsey, VI , THK. Caenis latipennis Banks Previous reports.?hamilton (1952) as C. forcipata: RED WILLOW (McCook). Provonsha (1990): BOX BUTTE (Niobrara R); CHASE (Cham pion L); CHERRY (Sparks); DAWES (Chadron St Coll Pond); FURNAS (Republican R); HITCHCOCK (Frenchman R); HOLT; LINCOLN (Jeffrey Res); SHERMAN (Mid Loup R). records.? BROWN: Plum Cr, Hwy 20 W Johnstown, VI , BCK; BUFFALO: Kearney at light, VIII , AVP; DUNDY: Republican R, Hwy 61 S Beukleman, V , Decker; FRANKLIN: Thompson Cr, Riverton, VII , Decker; GAGE: Turkey Cr, 4 mi N Holmesville, VII , THK; GARDEN: Blue Cr, Rocket Rd, V , BCK; HALL: pond, Mormon Is Rec Area, IV ; Platte R, St Rd 11/1-80, IV , WPM; JOHNSON: nr Elk Cr, VIII , THK; LANCASTER: Branched Oak L at Prk, VII , THK; LOGAN: S Loup R, Hwy 83, 1.3 mi N Stapleton, VI , BCK; NEMAHA: floodwaters Missouri R, Peru, VII , THK; SAUNDERS: Rock Cr, Ceresco, IV , Kaiisch; SCOTTS BLUFF: N Platte R, overflow pond, NE 71, IX , Harris; SHERIDAN: Niobrara R, VIII , Gibson; Niobrara R, Gordon, VIII , HRL; SIOUX: Niobrara R, Agate Springs Ranch, St Rd 29, VI , WPM; Agate Fossil Beds, Niobrara R, VII , BCK; WASHINGTON: Brown Cr, Co Rd 26, 41/30/33N 96/22/44W, VI , WPM. Caenis tardata McDunnough Previous reports.?provonsha (1990): DUNDY (S Frk Republican R); FURNAS (Republican R); HOLT; HITCHCOCK (Republican R); MERRICK (Platte R); SHERIDAN (Niobrara R); SHERMAN (Mid Loup R); WEBSTER (Republican R). records.? DAWES: Niobrara R, below Box Butte Dam, VIII , HRL; DODGE: Elkhorn R, St Rd 91,41 /32/21N 96/27/ 15W, VI , WPM; LOUP: Calamus R, Hwy 183,41/54/49N 99/23/09W, VI , WPM; SIOUX: Agate Springs at light, VII , HRL; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM.

13 W. P. MCCAFFERTY ET AL. 17 Caenis youngi Roemhild state records: BROWN: adult, Keller Prk St Rec Area, Hwy 183, 9.6 mi NE of Ainsworth, at light, VI , THK. Cercobrachys serpentis Sold?n state records: FURNAS: larvae & adults, Republican R, Oxford R channel, VIII , AVP; PAWNEE: larvae, N Frk Big Nemaha R, 1 mi E Table Rock, St Rd 4, VIII , THK; SHERIDAN: larvae: Niobrara R, Gordon, VII-11,VIII ; Niobrara R, S Gordon, VII , HRL. EPHEMERELLIDAE Ephemerella aurivillii (Bengtsson) Previous reports.?-decker (1981): FRONTIER (Medicine Cr); HAYES (Frenchman R); HITCHCOCK (Frenchman R, Republican R). Ephemerella inermis Eaton Previous reports.?carnevalo (1981), Carnevalo and Lunt (1982) as E. inermis, E. infrequens, or E. lacustris: BROWN (Long Pine Cr); CHERRY (Minnechaduza R, Niobrara R); KEYA PAHA (Keya Paha R); ROCK (Ash Cr). Decker (1981), Decker and Lunt (1982) as E. inermis or E. dorothea: FRONTIER (Medicine Cr); HAYES (Frenchman R); HITCHCOCK (French man R, Republican R). records.? BLAINE: Goose Cr, St Rd 7, S of Koshopah, VI , THK; DAWES: Niobrara R, below Box Butte Dam, VI , WPM; Niobrara R, Marsland, VI , HRL; LOUP: Calamus R, Hwy 183,41/56/49N 99/23/09W, VI , WPM; SHERIDAN: Niobrara R, Rt 87, IV , VI ; V , HRL; SIOUX: Niobrara R, Agate Springs Ranch, St Rd 29, VI , WPM; THOMAS: Dismal R, 13.9 mi S of Thedford, VI , THK; Mid Loup R, Thedford, V , HRL; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. EPHEMERIDAE Hexagenia bilineata (Say) Previous reports.?hamilton (1952): MADISON (Norfolk). Swanson (1967): KNOX (Lewis and Clark L [Missouri R]). records.? DAWES: Chadron at light, VIII , HRL. Hexagenia limbata (Serville) Previous reports.?spieth (1941): LANCASTER (Lincoln). Hamilton (1952, 1959): BUFFALO (Kearney); BROWN (Plum Cr); CHERRY (Minnechaduza R); DAWSON (Johnson L, Lexington, Willow Is); HALL (Wood R); KEITH (Ogallala); KNOX (Bazille Cr); LINCOLN (N Platte); MADISON (Norfolk); PLATTE (Columbus); SARPY (Linoma Beach ditch); SCOTTS BLUFF (Mitchell, Scottsbluff); SEW ARD (Milford, Seward); THOMAS (Halsey). Pesek (1974): LANCASTER (Salt Cr). Moul (1984): LANCASTER (Bluestem L). Harris et al. (1999): GAGE (Cub Cr); SIOUX (Niobrara R).

14 18 GREAT PLAINS MAYFLIES records.? BLAINE: N Loup R, Co Rd 1, 12 mi NW Brewster; Dismal R, St Rd 2 mi S Dunning, VI , BCK; BOX BUTTE: Niobrara R, XI , Muenchau; DAWES: Niobrara R, Marsland, VI , HRL; FURNAS: Oxford river channel & Oxford at light, VIII , AVP; GAGE: Homestead, 2.5 mi NW Beatrice, VI , BCK; KEYA PAHA: Niobrara R, Hwy 183 S Springview, VI , BCK; LOGAN: S Loup R, Hwy 83, 1.3 mi N Stapleton, VI , THK; NEMAHA: Auburn at light, VII ; Peru at light, VII , THK; RED WILLOW: Republican R, 1 mi S Perry; SHERIDAN: Niobrara R, St Rd 27, V , WPM; Niobrara R, Gordon, VIM , HRL; WHEELER: Cedar R, St Rd 70/91, E Ericson, 41 /47/00N 98/41 /53W, VI , WPM. Pentagenia vittigera (Walsh) Previous reports.?hamilton (1952, 1959): MADISON (Norfolk); PLATTE (Columbus). Swanson (1967): KNOX (Lewis and Clark L [Mis souri R]). records.? NEMAHA: Missouri R, Peru, VII , THK. HEPTAGENIIDAE Heptagenia diabasia Burks Previous reports.?hamilton (1952): BLAINE (Dismal R); HOLT (Ewing); KNOX (Bazille Cr); LOUP (Calamus R); MADISON (Norfolk); NEMAHA (Plum Cr); PIERCE (Pierce); PLATTE (Columbus); RICHARDSON (Falls City str); SCOTTS BLUFF (Scottsbluff irrigation canal). Carnevalo (1981): BOX BUTTE (Niobrara R); BROWN (Niobrara R); CHERRY (Minnechaduza R, Niobrara R); HOLT (N Br Verdigris Cr); KEYA PAHA (Keya Paha R); KNOX (Niobrara R); ROCK (Ash Cr); SEWARD (Seward); SHERIDAN (Niobrara R); SIOUX (Univ L); THAYER (Alexandria); THOMAS (Loup R); WASHINGTON (Herman str); WHEELER (Cedar R). Decker (1981): DUNDY (Republican R); FRANKLIN (Cottonwood Cr, Thompson Cr, Turkey Cr); FRONTIER (Medicine Cr); FURNAS (Muddy Cr, Republican R); HAYES (Frenchman R, Red Willow Cr); HITCHCOCK (Frenchman R, Republican R); RED WILLOW (Repub lican R); WEBSTER (Republican R). Angle (1987): SCOTTS BLUFF (Nine Mile Cr). Darrow and Preuss (1989): Lancaster (Haines Br). Harris et al. (1999): SIOUX (Niobrara R). records.? CASS: Platte R, Louisville L Prk, VII , THK; DAWES: White R, Whitney, VII ; White R, Crawford, VII ; Niobrara R, Marsland, VI ; Bordeaux Cr, VII ; Chadron Cr, VII , HRL; DODGE: Fremont at light; Elkhorn R, St Rd 91,41 /32/21N 96/27/ 15W, VI , WPM; DOUGLAS: Missouri R, Dodge Prk, Omaha, VI , THK; GAGE: Big Indian Cr, Hwy 77,1 mi S Wymore, V , THK; HALL: Platte R, St Rds 11/180, IV , WPM; JOHNSON: nr Elk Cr, VIII , THK; KEITH: Ogallala at light, VI , AVP; LINCOLN: N Platte at light, VII , AVP; LOGAN: S Loup R, Hwy 83,1.3 mi N Stapleton, VI , THK; PAWNEE: N Frk Big Nemaha R, St Rd 4,1 mi E Table Rock, VII ; Taylor Br, St Rds

15 W. P. MCCAFFERTY ET AL. 19 4/65, Table Rock, V , THK; VALLEY: N Loup R, Ord, park, VI , BCK. Heptagenia elegantula (Eaton) Previous reports.?traver (1935): LANCASTER (Lincoln). Hamilton (1952): MADISON (Norfolk); SEWARD (Seward). records.? BROWN: Bone Cr, Keller Prk St Rec Area, Hwy 183,9.6 mi NE Ainsworth; Long Pine Cr, Long Pine St Wildl Mgmt Area, 0.5 mi N Long Pine, VI , THK; DAWES: White R 8 mi NE Chadron, gravel rd, VI , WPM; Bordeaux Cr, III-30,V , , VII ; White R, Ft Rob, VI ; White R, Peters, VII ; White R, , VI ; White R, Whitney, VII ; White R, Ard Rd, VI ; White R, Crawford, VI-ll,VII-6, ; White R, N Chadron, V , HRL; NEMAHA: floodwaters Missouri R, Peru, VI , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8, 8 mi SW Humboldt, V , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Prk, VII , THK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; Niobrara R, VI ; Niobrara R, Peters, VIII ; Niobrara R, Gordon, VII , HRL; SIOUX: Agate at light, VII , HRL; THOMAS: Mid Loup R, entrance Neb Nat For, 1 mi W Halsey, VI , THK. Heptagenia flavescens (Walsh) Previous reports.?carnevalo (1981): BROWN (Niobrara R); KEYA PAHA (Keya Paha R); KNOX (Niobrara R). Decker (1981): DUNDY (Republican R); FRANKLIN (Cottonwood Cr, Thompson Cr); FURNAS (Muddy Cr, Republican R); HITCHCOCK (Frenchman R); RED WILLOW (Republican R); WEBSTER (Republican R). records.? CASS: Platte R, Louisville L Prk, VII , THK; DODGE: Fremont at light, VI , WPM; GAGE: Big Blue R, Chataqua City Prk, Beatrice, V , THK; NEMAHA: Auburn at light, VII ; floodwaters Missouri R, Peru, VII ; Missouri R, Brownville, VIII ; Peru St Coll at light, Peru, VI-5, , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, VII , THK. Leucrocuta hebe (McDunnough) Previous reports.?decker (1981) as Heptagenia: HITCHCOCK (French man R). Leucrocuta maculipennis (Walsh) Previous reports.?carnevalo (1981) as Heptagenia: KEYA PAHA (Keya Paha R). records.? DAWES: Chadron at light, VII , HRL; NEMAHA: Auburn at light, VIII ; Peru St Coll at light, Peru, VIII , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8, 8 mi SW Humboldt, VII , THK.

16 20 GREAT PLAINS MAYFLIES Macdunnoa persimplex (McDunnough) Previous reports.?traver (1935) as Heptagenia: LANCASTER (Lin coln). Hamilton (1952) as Heptagenia: MADISON (Norfolk); PIERCE (Pierce); SEWARD (Seward). records.? NEMAHA: Peru St Coll at light, IV-22, ,VI-21, ; Peru Boat Dock, VI , THK. Raptoheptagenia cruentata (Walsh) Previous reports.?traver (1935) as Heptagenia: LANCASTER (Lin coln). records.? DOUGLAS: Missouri R, Dodge Prk, Omaha, VI , THK; NEMAHA: Auburn at light, VI ; Peru St Coll at light, VI , THK. Stenacron interpunctatum (Say) Previous reports.?hamilton (1952) as Stenonema: DAWSON (Cozad); DODGE (Crowell); MADISON (Norfolk). Decker (1981): FRONTIER (Medicine Cr); FURNAS (Muddy Cr); HAYES (Frenchman R, Red Willow Cr); RED WILLOW (Republican R); WEBSTER (Republican R). Harris et al. (1999): GAGE (Cub Cr). records.? BUFFALO: S Loup R, Hwy 183, Milton Store, VI , BCK; DAWES: Bordeaux Cr, 7 mi N Chadron, V-24, ; White R, VI ; Chadron at light, VII , VIII-1,7-1998, HRL; LANCASTER: Branched Oak L at Prk, VII , THK; NEMAHA: Auburn at light, VIII ; Honey Cr, St Rd 67,2 mi SE Peru, VI ; Peru St Coll at light, Peru, VI , THK; PAWNEE: Taylor Br, St Rds 4/65, Table Rock, V , THK; RICHARDSON: Long Br, 1.1 mi E St Rd 105, V ; Muddy Cr, Hwy 73,1 mi W Verd?n, IV ; S Frk Big Nemaha R at light, St Rd 8, 8 mi SW Humboldt, VII , THK. Stenacron minnetonka (Daggy) Previous reports.?decker (1981): FRONTIER (Medicine Cr); HAYES (Red Willow Cr). Stenonema exiguum Traver state records: GAGE: larvae, Big Blue R, Chataqua City Prk, Beatrice, V , THK; RICHARDSON: larvae, S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, VII , THK; WHEELER: larvae, Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Stenonema femoratum (Say) state records: PAWNEE: larvae, Taylor Br, St Rds 4/65, Table Rock, VII , THK; RICHARDSON: larvae, Hwy 73,1 mi W Verd?n, III , THK. Stenonema mexicanum (McDunnough) Previous reports.?hamilton (1952) as S. bellum: CUMING (West Point). Carnevalo (1981), Carnevalo and Lunt (1982) as S. integrum: KNOX (Niobrara R). Decker (1981), Decker and Lunt (1982) as S. integrum:

17 W. P. MCCAFFERTY ET AL. 21 FURNAS (Muddy Cr); RED WILLOW (Republican R); WEBSTER (Re publican R). Darrow and Pruess (1989) as S. integrum: LANCASTER (Haines Br). records.? CASS: Platte R, Louisville L Prk, VII , THK; DODGE: Fremont at light, VI , WPM; DOUGLAS: Missouri R, Dodge Prk, Omaha, VI , THK; GAGE: Big Blue R, bridge Hoag, VI , BCK; Big Blue R, Chataqua City Pk, Beatrice, V , THK; NEMAHA: Floodwaters Missouri R, Peru, VII ; Mis souri R, Brownville, VIII ; Peru St Coll at light, Peru, VI , THK; PAWNEE: N Frk Big Nemaha R, St Rd 4,1 mi E Table Rock, VII 31,VIII , THK; RICHARDSON: S Frk Big Nemaha R at light, St Rd 8,8 mi SW Humboldt, VII-23,VIII , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Prk, VII , THK. E Stenonema modestum (Banks) Previous reports.?decker (1981) as S. rubrum: WEBSTER (Republican R). Stenonema pulchellum (Walsh) Previous reports.?"decker (1981): WEBSTER (Republican R). records.? LOUP: Calamus R, Hwy 183, 41/56/49N 99/ 23/09W, VI , WPM. Stenonema terminatum (Walsh) Previous reports.?hamilton (1952) as S. luteum: LANCASTER (Lin coln). Bednarik and McCafferty (1979): ANTELOPE (Neligh). Carnevalo (1981) as S. ares: KNOX (Niobrara R). Decker (1981) as S. ares: FURNAS (Republican R); FRONTIER (Medicine Cr); HITCHCOCK (Frenchman R). Klubertanz and Jones (1999): PAWNEE (N Frk Big Nemaha R); RICHARDSON (S Frk Big Nemaha R). records.? CASS: Platte R, Louisville L Prk, VII , THK; DAWES: White R, 8 mi NE Chadron, VI , WPM; White R, Slim Buttes, VII , HRL; DODGE: Fremont at light, VI , WPM; GAGE: Big Blue R, Chataqua City Prk, Beatrice, V ; Big Indian Cr, Hwy 77,1 mi S Wymore, V ; Plum Cr, 0.8 mi S St Rd 8 to Oketo, V , THK; LOUP: Calamus R, Hwy 183,41/56/49N 99/ 23/09W, VI , WPM; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; SIOUX: Spring Cr, V-1984, HRL; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. Stenonema vicarium (Walker) Previous reports.?-harris et al. (1999): GAGE (Cub Cr). records.? DODGE: adults, Fremont at light, WPM. VI , ISONYCHIIDAE Isonychia bicolor (Walker) state records: DODGE: adults, Fremont at WPM. light, VI ,

18 22 GREAT PLAINS MAYFLIES Isonychia rufa McDunnough Previous report s.? Hamilton (1952): MADISON (Norfolk); SEW ARD (Seward). Kondratieff and Voshell (1984): LANCASTER (Lincoln); LIN COLN (North Platte). Harris et al. (1999): SIOUX (Niobrara R). records.? BROWN: Plum Cr, Hwy 20 W Johnstown, VI ; Niobrara R, Hwy 183 S Springview, VI , BCK; CHERRY: Niobrara R, Rt 61, VI , BCK; DAWES: White R, 8 mi NE Chadron, VI , WPM; White R, Crawford, VII-6,VII ; White R, Slim Buttes, VII ; White R, Whitney, VII , HRL; DUNDY: Re publican R, Rt 43 W Bunckleman, VI , Opler; FURNAS: Oxford at light, VIII ; Republican R, Oxford, VIII , AVP; GARDEN: N Platte R, St Rt 27, VI , BCK; HAYES: Frenchman R, Rt 16 W Hamlet, VI BCK; KEITH: Ogallala at light, VI , AVP; KEYA PAHA: Niobrara R, Hwy 183 S Springview, VI , BCK; NANCE: Cedar R, St Rd 14 N Fullerton, VI , BCK; NEMAHA: Auburn at light, VII , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8,8 mi SW Humboldt, VII , THK; SCOTTS BLUFF: N Platte R, Scottsbluff, VII , BCK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; Niobrara R, Gordon, VI ; Niobrara R, Peters, VII ; Niobrara R, VII-3,VIII-9, , HRL; THOMAS: Dismal R, Co Rd off Hwy 83,13.9 mi S Thedford; Mid Loup R, entrance Neb Nat For, 1 mi W Halsey, VI , BCK; VALLEY: Mid Loup R, Arcadia, VI , BCK. Isonychia sicca (Walsh) Previous reports.?hamilton (1952): HARLAN (Republican City); MADISON (Norfolk). Traver (1935): LANCASTER (Lincoln). Klubertanz and Jones (1999): PAWNEE (N Frk Big Nemaha R). records.? DODGE: Elkhorn R, St Rd 91, 41/32/21N 96/ 27/15W, VI , WPM; FURNAS: Republican R, Oxford & Oxford at light, VIII , AVP; NEMAHA: Peru St Coll at light, Peru, VIII , THK; SARPY: Platte R, St Rd 31,1 mi E Schramm Prk, VII , THK; THOMAS: Dismal R, 13.9 mi S Thedford, VI , THK; WHEELER: Cedar R, St Rd 70/91 E Ericson, 41/47/00N 98/41/53W, VI , WPM. LEPTOHYPHIDAE Tricorythodes allectus (Needham) Previous reports.?wiersema and McCafferty (2000): HOLT (S Frk Elkhorn R). records.? BROWN: Long Pine Cr, Long Pine St Rec Area, 42/23/37N 99/42/35W, VI , WPM; FURNAS: Republican R, Ox ford, VIII , AVP; LOUP: Calamus R, US Hwy 183,41 /56/49N 99/ 23/09W, VI , WPM; PAWNEE: N Frk Big Nemaha R, 1 mi E Table Rock, St Rd 4, IX , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8 bridge, 8 mi SW Humboldt, VII , THK.

19 W. P. MCCAFFERTY ET AL. 23 Tricorythodes fictus Traver Previous reports.?hamilton (1952): PLATTE (Columbus). Tricorythodes minutus Traver state records: BROWN: larvae: Plum Cr, Hwy 20 W Jownstown, VI ; Bone Cr, Keller Prk St Rec Area, 9.6 mi NE Ainsworth, Hwy 183, VI , BCK; CHERRY: larvae, Niobrara R, Hwy 61, VI , BCK; DAWES: adults and larvae: Niobrara R, below Box Butte Dam, VI ; Chadron Cr, Chadron St Prk, VI ,16, ; White R, 8 mi NE Chadron at gravel rd, VI , WPM; Bordeaux Cr, Cliffs, V 31,26,VI-13,VII-5,13,16,30,VIII ; Chadron Cr, V-31,VI-4,25,26,VII 1,5,10,13,14,16,18, ; larvae: Niobrara R, Marsland, VI ; Pep per Cr, VII-10, ; Saw Log Cr, VIII ; E Ash Cr, VI-4,26,VII ; Bordeaux Cr, Ricks, VII ; White R, Slim Buttes, VII ; White R, Ard Rd, VI ; White R, Crawford, VI-ll,VII ; White R, Ft Rob, VI ; Soldier Cr, VII ; adults: W Ash Cr, VII 16,VIII , HRL; DAWSON: larvae, Platte R, Cozad, VI , AVP; HALL: larvae, Platte R, St Rd 11 and 1-80, IV , WPM; SIOUX: adults: Sowbelly Cr, Sowbelly Canyon 8 mi N Harrison, VI , WPM; Niobrara R, Agate at light, VI ; larvae, Soldier Cr, VI ll,vii-6,20,viii-2,ix ,hrl. LEPTOPHLEBIIDAE Leptophlebia cupida (Say) state records: SIOUX: larvae, Soldier Cr, 6 mi NW Fort Robinson, IV , HRL. Leptophlebia gravastella (Eaton) state records: DAWES: larvae: Fort Robinson Area, , Craft; Niobrara R, Marsland, VI ; Bordeaux Cr, IX ; E Ash Cr, X ; Chadron Cr, III-l , HRL. Leptophlebia nebulosa (Walker) Previous reports.?hamilton (1952): DODGE (Fremont); HALL (Wood R); PLATTE (Columbus pond). Harris et al. (1999): SIOUX (Niobrara R). records.? CHERRY: Cottonwood L St Rec Area; N Loup R, Rt 83; Rt 20, 8 mi W Merriman; Bear Cr, Rt 20, 2 mi E Eli turnoff; Minnechaduza Cr, Crookston, V , HRL; LOGAN: S Loup R, Rt 83, V , HRL. Neochoroterpes Oklahoma (Traver) state records: GAGE: adult, Plum Cr, 8 mi S St Rd 8 to Oketo, V , THK; PAWNEE: larvae, Taylor Br, St Rds 4/65, Table Rock, V , THK; RICHARDSON: subimago, Muddy Cr, Hwy 73, 1 mi W Verd?n, VIII ; adult, S Frk Big Nemaha R, St Rd 8, 8 mi SW Humboldt, V , THK.

20 24 GREAT PLAINS MAYFLIES Paraleptophlebia debilis (Walker) state records: DAWES: larvae, Bordeaux Cr (Cliffs), X , Craft. Paraleptophlebia gregalis (Eaton) state records: DAWES: larvae: Niobrara R, Marsland, IX , Muenchau; Chadron Cr, VI , HRL; SHERIDAN: larvae, Hay Springs Cr, V , HRL. OLIGONEURIIDAE Homoeoneuria ammophila (Spieth) Previous reports.?carnevalo (1981): CHERRY (Niobrara R); KNOX (Niobrara R). records.?furnas: Republican R, Oxford R channel, VIII , AVP; SHERIDAN: Niobrara R, VIII-9, ; Niobrara R, S Gordon, VII ; Niobrara R, Gordon, VII , HRL. POLYMITARCYIDAE Ephoron album (Say) Previous reports.?traver (1935): DUNDY (Arikaree R); Hamilton (1952,1959): CHERRY (Snake R); DAWSON (Cozad); DUNDY (Rock Cr); FRONTIER (Curtis); SCOTTS BLUFF (Scottsbluff Canal); SIOUX (Uni versity L); Decker (1981): FRONTIER (Medicine Cr). records.? DAWES: White R, VIII , HRL; FURNAS: Oxford at light, VIII , AVP; GREELEY: Cedar R, St Rd 91,41/41/ 50N 98/25/23W, VI , WPM; NEMAHA: Peru at light, VII , THK; PAWNEE: N Frk Big Nemaha R, St Rd 4,1 mi E Table Rock, VIII , THK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM. Tortopus primus (McDunnough) Previous reports.?hamilton (1952, 1959): BUFFALO (Kearney); DAWSON (Cozad); MADISON (Tri-County Canal). McCafferty (1975): WASHINGTON (Fort Calhoun). records.? NEMAHA: Missouri R, Peru, aquatic light trap, VII , THK; RICHARDSON: S Frk Big Nemaha R, St Rd 8,8 mi SW of Humboldt, at light, VII , THK. PSEUDIRONIDAE Pseudiron centralis McDunnough Previous reports.?hamilton (1952): PLATTE (Columbus). Decker (1981): DUNDY (Republican R); HITCHCOCK (Frenchman R, Republi can R); RED WILLOW (Republican R). Pescador (1985): LINCOLN (S Platte R). McCafferty and Provonsha (1986): no indicated (Niobrara R). records.? BLAINE: N Loup R, Co Rd 1, VI , THK; NEMAHA: Auburn at light, VII ; Peru St Coll at light, VI ,

21 W. P. MCCAFFERTY ET AL. 25 THK; SHERIDAN: Niobrara R, St Rd 27, VI , WPM; THOMAS: Dismal R, 13.9 mi S Thedford, VI , THK; VALLEY: N Loup R, VI , BCK; WHEELER: Cedar R, St Rd 70/91,41 /47/00N 98/41 /53W, VI , WPM. SIPHLONURIDAE Siphlonurus columbianus McDunnough state records: HALL: larvae, Platte R, St Rd 11/1-80, IV , WPM. Siphlonurus occidentalis (Eaton) Previous reports.?decker (1981), Decker and Lunt (1982): DUNDY (S Frk Republican R); HITCHCOCK (Republican R). ACKNOWLEDGMENTS Funding for this research was provided in part by National Science Foundation Grant DEB to WPM and Chadron State College Research Institute Grant to RHL. The paper has been assigned Purdue Agriculture Research Program Journal No LITERATURE CITED Angle, L Effects of sediment addition on the drift of aquatic macroinvertebrates in Nine Mile Creek, Nebraska. Unpublished Masters Thesis, University of Nebraska, Lincoln. Bednarik, A. F. and W. P McCafferty. Biosystematic revision of the genus Stenonema (Ephemeroptera: Heptageniidae). Canadian Bulletin of Fisheries and Aquatic Sciences 201: vi Carnevalo, M. A The ecology and distribution of Ephemeroptera (mayflies) along the Niobrara River system in northern Nebraska. Unpublished Masters Thesis, University of Nebraska, Omaha. Carnevalo, M. A. and S. R. Lunt Abstract of "Ecology and Distribution of in mayflies the Niobrara River system in Nebraska." Proceedings of the Nebraska Academy of Science and Affiliated Societies 92: 9. Darrow, P. O. and K. P Pruess Effects of substrate on of density aquatic insects in a southeast Nebraska stream. Transactions of the Nebraska Academy of Science 17: Decker, M. L The distribution and ecology of mayflies (Ephemeroptera) in the Republican River and its tributaries in Nebraska. Unpublished Masters Thesis, University of Nebraska, Omaha. Decker, M. L. and S. R. Lunt Abstract of and "Ecology Distribu tion of mayflies in the Republican River system in Nebraska." Proceedings of the Nebraska Academy of Science and Affiliated Societies 92: 9.

22 26 GREAT PLAINS MAYFLIES Hamilton, E. W A taxonomic study of the Ephemeroptera of Nebraska. Unpublished Masters Thesis, University of Nebraska, Lincoln. Hamilton, E. W Review of Ephemeridae (Ephemeroptera) in the Missouri River Watershed with a key to the species. Iowa State College Journal of Science 33: Harris, M. A., B. C. Kondratief f and T. P. Boyle Macroinvertebrate community structure of three prairie streams. Journal of the Kan sas Entomological Society 72: Klubertanz, T. H and D. M. Jones Adults of Camelobaetidius waltzi (Ephemeroptera: Baetidae) with field notes. Entomological s 110: Kondratieff, B. C. and J. R. Voshell, Jr The North and Central American species of Isonychia (Ephemeroptera: Oligoneuriidae). Transactions of the American Entomological Society 110: McCafferty, W. P The burrowing mayflies of the United States. Transactions of the American Entomological Society 101: McCafferty, W. P Comparison of Old and World Acanthametropus (Ephemeroptera: Acanthametropodidae) and other psammophilous mayflies. Entomological s 102: McCafferty, W. P. 2000a. The gentle quest: 200 years in search of North American mayflies. In: E. Dom?nguez (ed.). Trends in research in Ephemeroptera and Plecoptera. Kluwer Academics/Plenum, York. In press. McCafferty, W. P. 2000b. A new Nearctic Apobaetis (Ephemeroptera: Baetidae). Entomological s 111: McCafferty, W. P. and A. V. Provonsha Comparative mouthpart morphology and evolution of the carnivorous Heptageniidae (Ephemeroptera). Aquatic Insects 8: McCafferty, W. P. and R. P. Randolph Canada mayflies: a faunistic compendium. Proceedings of the Entomological Society of Ontario 129: W. P. McCafferty, and R. D. Waltz Baetis magnus, new species, formal new name for Baetis sp. B of Morihara and McCafferty (Ephemeroptera: Baetidae). Proceedings of the Washington Ento mological Society 88: 604. Moul, J. M Prevalence and relationships of two allocreadiid Metacercariae in the burrowing mayfly, Hexagenia limbata (Serville in Guerin), of Bluestem Lake, Lancaster County, Nebraska. Trans actions of the Nebraska Academy of Sciences 12: Pescador, M. L Systematics of the Nearctic genus Pseudiron (Ephemeroptera: Heptageniidae: Pseudironinae). The Florida En tomologist 68: Pesek, T. F Macroinvertebrates as indicators of water in quality Salt Creek, Nebraska. Unpublished Masters Thesis. University of Nebraska, Provonsha, Lincoln. A. V A revision of the genus Caenis in North America (Ephemeroptera: Caenidae). Transactions of the American Ento mological Society 116: