Biodiversity Canada Sask.
Biodiversity 2
Living Fossil??
Identification, Taxonomy papers
Environmental Laws, Canada
Species of Concern
Oldman Dam Alberta
Alberta Update 2010
Saskatchewan Update
Saskatchewan River
Aquatic Insects
Mayflies, Sask. River
Plecoptera, Sask. River
Caddisflies-Sask. Riv.
Chironomidae, Diptera, Sask. Riv.
Mosquitoes Culicidae
Oregon Winter Ponds
Oregon Rivers Intro
Willamette River
Columbia River
Missouri River
China Yangtze River
Arctic Canada, Rankin
MacKenzie River Canada
Fish- Rivers
Teaching Materials


Those troublesome Adult Mayflies (Ephemeroptera)
Below are Tables for the identification of adult mayfly Families.  Mayflies have a large number of veins in the wings, and these veins are important  for the identification of Families.  Most people find the wings to be very confusing, including myself, and  I made  summary tables to simplifythe process easier for my own use.  This was published in 1975, and a cut and paste version is given below.  (Complete keys are readily available in Entomology textbooks).

Mayflies 0 Lehmkuhl 1976 complete0001.pdf
Complete Paper Lehmkuhl 1976.
(Old Classification of Familes, see notes)
Caenidae, Tricorythidae,
Polymitarcidae, Ephemeridae

see notes below
Baetidae, Heptageniidae,
Leptophlebiidae, Baetiscidae,Siphlonuridae

Mayflies 3 Adult identification I and II Lehmkuhl0001.pdf

Mayflies 4 Adult identification III and IV Lehmkuhl0001.pdf

Mayflies 5 Adult identification V and VI Lehmkuhl.pdf
Notes: For Tricorythidae,
see Leptohyphidae.
Notes:for Pseudiron, see Pseudironidae. Metretopus is now in
Also, see below on this page
Family names have had some
changes, see below.

Mayflies 1 Intro Lehmkuhl.pdf

Mayflies 2 Figs. adults immatures Lehmkuhl0001.pdf

Mayflies 6 Species list 1975, Refs. Lehmkuhl.pdf
Introduction to
above paper
Some figures of adults and
Note: List of Sask. species, 1975.  Note  at least 15 species of
"Baetis", most with ??.  Keys
to species are now available.
Epeorus sp. became
Acanthamola pubescens, and
Anepeorus became
see additional
species of interest.

General Comments and Informatio

Mostly about Saskatchewan in general, but also Mayflies specifically associated with the Saskatchewan River

Some Comparisons

See  Oregon Mayflies    and Oregon Species


In  Oregon, Mayflies comprise  11 Families, 45 genera, and 142 species according to the above reference. 

In Saskatchewan there are 18 families  and about 54 genera and about 107 species. 

In the Saskatchewan River there are 15 families, and  44 genera representing approximately 58 species.

In Alberta there are 15 Families, 38 genera, and 92 spp. (McCafferty and Randolph, 1998)

See also Montana List    www.esg.montana.edu/aim/ephem/ephem0.html

     About 125 species are listed for Montana, and notice in the link above the large number of  typical mountain groups  found there, that is, species of Ephemerellidae, Ameletidae, and Heptageniids of the genera Cinygmula, Epeorus,  and Rhithrogena.  Compared to Saskatchewan, where few of these are present.   There is a great overlap in Montana/Saskatchewan species in the Genera Choroterpes, Traverella, Lachlania, Macdunnoa, Ametropus, and others, and these are reported from eastern Montana, and are known also from the Saskatchewan River System.

see also Mayflies of the World  www.insecta.bio.pu.ru/z/Eph-spp/Contents.htm

Return Aquatic Insect Page     Home


     Aside from aquatic biologists and entomologists, mayflies  are  well known among fishermen, who  tie flies that mimic mayfly larvae, subimagos, and adults (above).  Many fishermen are very knowledeable about this group, often surpassing scientists in their knowledge of the Order Ephemeroptera  and individual species and genera (e.g. google Western Hatches by Rick Hafele and David Hughes or  Great Rivers, Great Hatchdes by Charles Meck and Greg Hoover) .  One of the best academic sources is Edmunds, G.F. Jr., S.L. Jensen and L. Berner. 1976. The Mayflies of North and Central America. University of Minnesota Press, Minneapolis. More references are given at the end of this page and in Selected References.

About 650 species of mayflies (Ephemeroptera) are found in North America north of Mexico.  Both Canada and Saskatchewan have a rich  mayfly fauna. Twenty families and about 325 species  found in Canada. In Saskatchewan there are 18 familiea  and about 54 genera and about 109 species.  In the Saskatchewan River there are 58 species, representing --Genera and 18 Families. 


A list of Saskatchewan species is given below.  At the end of this page is a discussion for  Saskatchewan River Species (not Boreal species) .


A thesis done in my lab, Webb (2003) , cited below and elsewhere on thes pages, is a careful study and source of accurate information.


Ephemeroptera (Mayflies) of Saskatchewan)


Analetris eximia Edmunds (drawing below) (details)




Ameletus oregonensis McDunnough

Ameletus subnotatus Eaton


Ametropus neavei McDunnough (Drawing below) (details).



Arthroplea bipunctata (McDunnough)


Acentrella insignificans (McDunnough),

Acentrella parvula (McDunnough)

Acentrella turbida (McDunnough)

Acerpenna pygmaea (Hagen)

Apobaetis indeprensus Day

Baetis bicaudatus

Baetis brunneicolor McDunnough

Baetis bundyae Lehmkuhl

Baetis flavistriga McDunnough 

Baetis hudsonicus Ide

Baetis hudsonicus

Baetis intercalaris McDunnough 1921

Baetis tricaudatus Dodds

Callibaetis ferrugineus Walsh

Callibaetis pallidus Banks

Callibaetis skokianus Needham?????? NOT IN WEBB 

Camelobaetidius warreni (Traver and Edmunds)

Centroptilum album McDunnough

Centroptilum bifurcatum McDunnough

Centroptilum conturbatum McDunnough,  

Centroptilum victoriae McDunnough

Cloeon dipterum (Linnaeus)

Diphetor hageni (Eaton)

Fallceon quilleri (Dodds)

Plauditus cestus (Provonsha and McCafferty)

Plauditus dubius (Walsh)

Plauditus punctiventris (McDunnough)

Plauditus gloveri Macfferty and Walsh

Plauditus virilis (McDunnough)

Procloeon ingens (McDunough)

Procloeon irrubrum Lowen and Flannagan

Procloeon pennulatum (Eaton)

Procloeon quaesitum (McDunnough)

Procloeon rivulare (Traver), NOT IN WEBB

Procloeon rubropictum   (McDunnough)

Procloeon rufostrigatum (McDunnough),

Procloeon simplex (McDunnough)

Pseudocloeon dardanum (McDunnough)

Pseudocloeon propinquus (Walsh)


Baetisca lacustris McDunnough (Sask River Lemsford Ferry)(not B. bajkovi)

Baetisca laurentina McDunnough ( mostly tributary streams, Red Deer River)(not B. obesa)

(Current corrected taxonomy above)



Brachycercus edmundsi (Allen)

Brachycercus prudens (McDunnough)

Caenis amica Hagen

Caenis hilaris (Say)

Caenis latipennis Banks,

Caenis tardata McDunnough

Caenis youngi Roemhild

Cercobrachys cree Sun, Webb and McCaffety



Drunella grandis (Eaton)

Ephemerella inermis Eaton

Ephemerella needhami McDunnough

Eurylophella bicolor (Clemens)

Eurylophella temporalis (McDunnough)

Serratella serrata (Morgan)

Serratella tibialis (McDunnough)

Timpanoga lita (Burks)

Timpanoga simplex (McDunnough)


Ephemera simulans Walker ,

Hexagenia limbata (Serville)


Acanthamola pubescens Whiting and Lehmkuhl  original description in pdf below

Acanthamola Whiting and Lehmkuhl.pdf

Anepeorus rusticus McDunnough

Cinygmula mimus (Eaton)

Epeorus longimanus (Eaton)

Heptagenia adaequata McDunnough

Heptagenia diabasia Burks

Heptagenia elegantula (Eaton)

Heptagenia flavescens (Walsh)

Heptagenia pulla (Clemens)

Leucrocuta hebe (McDunnough)

Leucrocuta maculipennis (Walsh)

Macdunnoa nipawinia Lehmkuhl (original description and drawing below)

Macdunnoa original desc Lehmkuhl.pdf


Nixe inconspicua (McDunnough)

Nixe lucidipennis (Clemens)

Nixe rusticalis (McDunnough)

Nixe simplicoides (McDunnough)

Raptoheptagenia cruentata  original description with details in pdf below

whiting and Lehmkuhl, Raptoheptagenia.pdf

Rhithrogena jejuna Eaton NOT IN WEBB

Rithrogena undulata (Banks)

Stenacron interpunctatum (Say)

Stenonema femoratum (Say)

Stenonema terminatum (Walsh)

Stenonema vicarium (Walker)


Isonychia campestris McDunnough


Asioplax corpulenta (Kilgore and Allen),

 Asioplax edmundsi (Allen) CHECK WEBB

Tricorythodes minutus Traver


Choroterpes albiannulata McDunnough

Leptophlebia cupida (Say)

Leptophlebia nebulosa (Walker)

Paralepthophlebia adoptive (McDunnough)

Paralepthophlebia debilis (Walker)

Paralepthophlebia moerens (McDunnough)

Paralepthophlebia praepedita (Eaton)

Traverella albertana (McDunnough)


Metretopus borealis (Eaton)

Siphloplecton basale (Walker)

Siphloplecton interlineatum (Walsh)


Lachlania saskatchewanensis Ide (drawing below) (details)

POLYMITRACIDAE Ephoron album (Say)


Pseudiron centralis McDunnough (drawing below) (details)



Parameletus chelifer Bengtsson

Siphlonurus alternatus (Say)


Ephemeroptera- Saskatchewan River:

Comments on and review  of  the mayflies of the Saskatchewan River and other Prairie flowing waters (excluding the Boreal Forest, but including the Cypress Hills).

      Information below is from personal observations plus Edmunds, Jensen, and Berner (1976), Lehmkuhl (1970, 1976,1979, and 1980) and Webb (2002).   See  Merritt and Cummins (1996) for an extensive bibliography. See also Selected References and references at the bottom of this page.

            The first family and species discussed below illustrates but one of many examples of the unique and special community of aquatic insects found in the Saskatchewan River System.   Analetris eximia Edmunds  is one of the rarest mayflies in North America (Edmunds, Jensen, and Berner, 1976).  Other rare and unusual species include (all Ephemeroptera)  Pseudiron centralis McDunnough, with rare  predatory larvae which have a unique crablike body with very long tarsal claws allowing  movement forward, backward, or sideways over submerged sandbars while it sweeps the sand with long palps seaching fore chironomid larvae which are its prey , Lachlania saskatchewanensis Ide, with nearest relatives in the Neotropical,  and having unusual body features such as filter feeding setae in rows on the front legs, and  Acanthamola pubescens Whiting and Lehmkuhl,  which is extremely rare and  presumably endangered.     Other  unique and special mayflies in prairie rivers include members from  the genera Camelobaetidius , Traverella, and Choroterpes, -also with relatives in the Neotropical, and  Metretopus, being found also  in Scandinavia.   Ametropus is  rare and specialized mayfly living on sandbars.   Families and species will be discussed in the following pages.

Saskakatchewan River Mayflies- annotations and comments


            The above family contains  two genera,  Acanthametropus Tshernova  from the east central US.,


and Analatris Edmunds from Saskatchewan, Alberta, Wyoming, and Utah.  Both are seldom collected and apparently endangered, although I have found large populations of A. eximia  Edmunds in past years in the Saskatchewan River. 


They are very strong swimmers, and this contributes to the fact that they are seldom collected, and they are unusual because they are predators, feeding on Chironomid larvae.    


       Ameletus  Eaton  is the only genus in the family, and there is a large number of species found in cool swift streams, especially  in Rocky Mountains, Cascades, and Coast Range of western North America.  Two species are found in the prairies, A. oregonensis  McDunnough in  the Cypress Hills of Alberta and Saskatchewan, and A. subnotatus Eaton  is known from the Boreal forest area.


      Ametropus Albarda is the only genus in the Family and it is holarctic.  A. neavei McDunnough  is a large river specialist and is found on clean sand substrates in the Saskatchewan River System.  It has specialized setae in the head region and on the front legs, and it filters food from the passing current while the posterior 4  legs anchor it on the fine sand of submerged sand bars.  They can quickly bury themselves by means of a shivering action when disturbed. The same species is found in the Colorado River system. (see discussion of species name)


 Arthroplea Bengtsson is the only genus in the family and A. bipunctata (McDunnough) is found in the north but so far not from prairie rivers.  They have unusual long palps for gathering food.  It is seldom collected and is rare in the region.


           Members of this family  are interesting and important because they are often very abundant in  lotic (flowing) waters.  At the species level, biodiversity of  Baetids show  that  various species  have come to the prairies  from the circumpolar, the central grasslands, the Boreal,  the east, and the far southwest, following post-glacial routes of colonization yet to be deduced.  Discussions and details can be found in Webb (2002),  Lehmkuhl (1980).   Christiansen (1979) is also useful.   The number of genera is large because  Baetis Leach  has recently been divided into a number of genera.  All Baetis and  former members of the genus Baetis  are small (e.g. 5 mm) and  torpedo shaped, excellent swimmers in fast currents, and are  often very abundant and are extremely important in the food chain and ecology of flowing waters.

            Acentrella  Bengtsson members are typical “Baetis” in body  form and habits. A. insignificans (McDunnough), A. turbida  (McDunnough), and A. parvula (McDunnough) are common in the Sask. River system and boreal streams and rivers.   

            Acerpenna Waltz and McCafferty members are also former  “Baetis”.  A. pygmaea  (Hagen) is common in the Saskatchewan River system and  the Boreal forest.

            Apobaetis is represented by A. indeprensus and is rather rare in the South. Saskatchewan River but is widespread.  It is a large river specialist found on shifting sand bars.  A. lakota McCafferty was described from North Dakota and Nebraska and may eventually be found in Canadian prairie rivers.

             Baetis Leach is represented in prairie flowing waters by at least five species, and a total of 7 are known from Saskatchewan including Boreal streams.    B. bicaudatus  Dodds is a western N. A. species and is  found in the northern Boreal as well as Battle Creek in the Cypress Hills;   B. brunneicolor  McDunnough is a widespread eastern species, also widespread in Saskatchewan, from the Saskatchewan River system and the Cypress Hills;  B. flavistigra McDunnough is an eastern species that is   widespread in the  Saskathewan boreal, absent from the Saskatchewan River system, but found in streams in the Cypress Hills;  B. intercalaris McDunnough is an eastern species found in smaller Saskatchewan rivers;  B. tricaudatus Dodds  is widespread in N. A. and  is widespread in  Saskatchewan streams and rivers. Other Saskatchewan species include B. bundyae Lehmkuhl and B. hudsonicus Ide.

            Callibaetis Eaton members are common in lakes, ponds, and slow moving portions of streams. C. ferrugineus  (Walsh) and C. pallidus  Banks are widespread in Saskathewan .

            Camelobaetidius Demoulin species are mostly from silty rivers from Mexico to South America but also in the SWUS  (e.g. Utah) plus the Saskatchewan River system in the prairies.  They  have unique spatulate claws.   C. warreni Traver and Edmunds  is part of the unique mayfly community at Lemsford Ferry, where many southwestern species are found (e.g. Lachlania saskatchewanensis Ide, Traverella albertana, and others).           

            Centroptilum Eaton is represented by 15 species in  North America, and four (probably eventually 6) species are known from the streams and rivers of  the prairies. Of the Saskatchewan species, C. album McDunnough is widespread in North America,  C. bifurcatum McDunnough is northern by comparison,  C. conturbatum  McDunnough is northern and western,  and C. victoriae McDunnough is restriced to Canada, ranging  from Saskatchewan eastward.   C. walshi McDunnough and C. convexum Ide   are known from Manitoba.

            Cloeon Leach has a single species in North America, and  C. dipterum (Linnaeus) is known from oxbow  lakes of the Saskatchewan River..

            Diphetor Waltz and McCafferty, contains a single species, D. hageni (Eaton) which is widespread in  N.A., and has been collected from the Cypress Hills and Boreal streams.  As is the case with the nearby site of Lemsford Ferry on the South Saskatchewan River, where a number of SWUS  species can be found, unique and unusual communities can be found in the Cypress Hills, where  there are associations with the Rocky Mountains and the Black Hills of South Dakota..

            Falceon Waltz and McCafferty members were formerly in Baetis, and the group of four species probably has a South American center of origin.   Only one species, F. quilleri (Dodds)  is widespread in North America and it is found west of  Indiana and Louisiana and is present in the Saskatchewan River system from  July to September.

            Plauditus Lugo-Ortiz and McCafferty was erected for thirteen  species formerly in Pseudocloeon  Klapalek and Baetis, and thus they are  all small, torpedo shaped excellent swimmers found in flowing water.   P. cestus (Provonsha and McCafferty),  P. dubious (Walsh),  P. punctiventris  (McDunnough),  P. virilus (McDunnough), and P. gloveri (McDunnough) are found in the Saskatchewan River system and in Boreal rivers.  Some species appear to have limited distributions associated with specific local stream habitats and ecological conditions, while others are widespread and occur in a variety of conditions.

            Procloeon Bengtsson  is a large  and poorly known group of Baetids,  with 25 species named from North America.   Seven  species occur in Saskathewan rivers and streams, these being P. ingens (McDunnough), P. irrubrum  Lowen and Flannagan,  P. pennulatum Eaton,  P. quaesitum (McDunnough),  P. rubropictum (McDunnough),  P. rufostrigatum (McDunnough), and P. simplex  (McDunnough).  Because of the diversity, widespread occurrence, and abundance under certain conditions, members of of this genus are of ecological importance as herbivores and detitivores in prairie flowing water systems.   

         Pseudocloeon Klapalek has undergone major taxonomic changes, with previous members moved to several other genera, and the genus now consists of the former members of the propinquus group of the genus Baetis (Webb 2002).  Two of the six North American species occur in the prairies, these being P. propinquum (Walsh) and P. dardanum (McDunnough);  these  are widespread  in the Saskathewan River system.

Further  Comments on Baetidae in the Prairies.

            About 3 dozen species of Baetids are known from Saskatchewan, and nearly all are 1 cm or less in length, are all torpedo shaped with long antennae, are excellent swimmers,  and are often extremely abundant and contribute to the biomass, food chain, and functioning as gatherers and scrappers of organic debris, diatoms, and organic growth in flowing water systems 

            In ecological studies, it is  common that all of these are lumped as Baetis spp.  or Baetidae, but it is obvious that a great many tolerances, sensitivities, life cycles, and habitats, as well as biogeographic and evolutionary background  are represented.  When considering pollution or ecological function it may not be acceptable to lump all these together if a clear understanding of ecosystems is desired.  While accurate and precise taxonomy require knowledge and skill, and some groups remain poorly known both biologically and taxonomically, works such as Webb (2002 ) now mean that species level work is certainly possible, and should be done when it is necessary.


            This family is restricted to North America, mostly the east, and has the single genus Baetisca.  The 12 species are well known and attract attention because of the large mesonotum that gives larvae a very hump-backed appearance and also often the presence of long dorsal and lateral spines from the thorax.  B. lacustris and B. laurentia are known from the flowing waters of the prairies.


             Three of the four genera in this family occur in the prairies.  Larvae have large dorsal quadrate gills on segment 2 of the abdomen which cover the posterior gills, possibly with the function  of preventing silt from settling on the latter.  Adults are tiny and lack hind wings.  Members can be very abundant and especially  larvae  are important ecologically. 

            Brachycercus Curtis has 10 North American species and B. prudens (McDunnough)  and B. edmundsi  Soldan are known from the Saskatchewan River system and other flowing waters in the prairies..

            Caenis Stephens members are usually found in slow moving or still waters and the tiny white adults can be very abundant around lights at night.  C. amica Hagen, C. hilaris (Say), C. tardata McDunnough, C. latipennis  Banks, and C. youngi  Roemhild are found in prairie rivers and ponds. 

            Cercobrachys Soldan is a genus widespread in the world with 3 North American species.  Ecology and biology are poorly known.  C. cree Sun, Webb, and McCafferty is known form large warm rivers in the prairies, especially Lemsford Ferry on the South Saskatchewan River.


            Ephemerella  in the broad sense once contained all the numerous species in this family, but now the subgenera have been given full genus status, so that Ephemerella Walsh  now has a narrower definition. Three genera are found in the prairies and more are known from the Boreal Forest. Larvae of this family are easily recognized by the somewhat flattened body, the laterally splayed legs, and the tough and strong appearance of the exoskeleton, in contrast to the more delicate and streamlined appearance of most  mayfly larvae. Members may be very abundant in some situations in flowing water so they are of considerable ecological importance as consumers of debris and algal growth, and as a food source for secondary consumers.

                        Dannella Edmunds  is represented by D. lita  (Burks) and D. simplex  (McDunnough) in the praires..

            Ephemerella Walsh members are large for mayflies and may be very abundant in prairie rivers.  E. needhami  McDunnough and E. inermis  Eaton are found in the Saskatchewan River system, and the latter is sometimes very abundant.

    ??       Eurylophella Tiensuu are common in slow water or at  lake margins.
E. temporalis  (McDunnough) and E. bicolor  (Clemens)are found in streams bordering the prairies and the Boreal Forest.


            Members of this family include some of the largest mayflies, and they may occur in huge numbers deep in lakes and also in rivers and streams.  Larvae make U shaped burrows in mud and gravel and filter out organic material as food.  They are very important as part of the food chain leading to fish.

            Ephemera Linnaeus has 6 species in North America, and E. simulans Walker  is found in the prairies, in both lotic and lentic waters.  These are very important in the ecology of lakes and rivers as fish food and in processing benthic deposits of mud and organic material.

            Hexagenia Walsh has 5 North American species that are large and conspicuous burrowers found in both lotic and lentic waters.  They are  also very important in the ecology of aquatic habitats, being part of the food chain and also processing organic materials an mineralizing nutrients.  H. limbata  (Serville) is common and widespread  in the prairies.


            This family is very large, and, even though members are almost entirely restricted to flowing waters and associated with mountain streams and clear cold water,  twelve of the fourteen North American genera are found in Saskatchewan.  About 10 are known from prairie rivers, supporting the idea the the Saskatchewan River is really a mid level stream from an ecological point of view, and not a river in the sense of many depositional zones and possibly turbid and relatively slow water flow. The Saskatchewan River has an especially diverse fauna of Heptageniids and is  the type locality for several  recently discovered genera and species.

             Heptageniids  are very important ecologically as flattened gatherers and scrapers on stone and wood substrates and may represent a large biomass.  They are also of great interest due to the unusual nature of some species, such as the predatory habits of Acanthamola Whiting and Lehmkuhl  and others, carnivory being very rare in the Ephemeroptera.

            Acanthamola Whiting and Lehmkuhl contains the single species A. pubescens Whiting and Lehmkuhl.  In previous years it was quite abundant at Lemsford Ferry on the South Saskatchewan River, but recent attempts to collect them have not been successful.  The adults are unknown. It is very rare and seemingly endangered, and it  predatory, an unusual thing in the Ephemeroptera. See details in the pdf below.

Acanthamola Whiting and Lehmkuhl.pdf

            Anepeorus McDunnough has two species, one of which is eastern.   A. rusticus McDunnough was collected as adults near the Saskathewan River.  None have been collected for about 80 years and it is considered to be rare and endangered.  Larvae are unknown.  The taxonomic situation is complex and uncertain (Webb 2003). Compare :

Acanthamola Whiting and Lehmkuhl.pdf

             Epeorus Eaton are associated with cold swift streams, and one species,  E.   longimanus (Eaton) is found in the Rocky Mountains and also  in the Cypress Hills.

            Heptagenia Walsh has 12 North American species and five are found in the prairie flowing waters.  They are often a very important part of the community in terms of being part of the food chain and in their role as gatherers and scrapers. In the Saskatchewan River system, almost any rock or submerged branch will have a number of specimens and species of this genus (along with numerous Baetis species and individuals).  The flattened bodies of the Heptagenia allow them to graze on the surfaces and undersides of solid substrates.  In Saskatchewan the species  found are  H. adequata  McDunnough, H. diabasica  Burks, H. elegantula (Eaton), H. pulla  (Clemens) , and H. flavescens  (Walsh).

            Leucrocuta Flowers contains 10 North American species and members were once considered to be in the genus Heptagenia.  There are two species in the prairies : H. hebe  (McDunnough) and H. maculipennis .  The latter made a sudden recent and abundant appearance in the Saskatchewan River for unknown reasons (p.195, Webb 2002).

Maccaffertium terminatum- as Stenonema

                        Macdunnoa Lehmkuhl was described from larvae from the Saskatchewan River. The type species is  M. nipawinia Lehmkuhl and is a rare species known only from here and the Milk River, Alberta.  Larvae occupy a typical Heptageniid habitat, but are especially fond of partially rotted wood.  In the field can be easily identified by the almost solid black body with a couple of white spots.  None have been collected recently, and they we always found in small numbers.  Adults are now known.

Macdunnoa original desc Lehmkuhl.pdf

                        Nixe Flowers is a group formerly in the genus Heptagenia, and  four species, H. inconspicua (McDunnough), N. lucidipennis  (Clemens),  N. rusticallis  (McDunnough), and N. simplicoides (McDunnough), are known from Saskatchewan  They are more likely to be found in Boreal streams than the prairies.

            Raptoheptagenia Whiting and Lehmkuhl

            This genus was described as new to fit larva mistakenly thought to be Anepeorus sp.    R. cruentata (Walsh)  is very rare but widespread  and was previously quite abundant in the Saskatchewan River system.  It has a predatory larva, making it very unusual among the Ephemeroptera.  


whiting and Lehmkuhl, Raptoheptagenia.pdf

            Rhithrogena Eaton is represented by two species in the prairies. The underside of larvae have gills modified into an almost perfect suction cup for dealing with swift water currents, and most of the 22 North American species are found in the mountains of the west and northeast.     R. jefuna  Eaton and R. undulata (Banks) are found in Saskatchewan, the latter restricted to the pristine river at Lemsford Ferry on the South Saskatchewan River.

            Stenacron Jenson was formerly part of the genus Stenonema Traver and both genera have members that  are  abundant in river and stream benthos along with Heptagenia.  These three genera are the most abundant Heptageniids on rocks and branches in the Saskatchewan River system.   Of seven North American species, one, S. interpunctatum  (Say), is found in the Boreal and prairies..      

Stenonema Traver is well known taxonomically as both adults and larvae, and fifteen species are found in eastern North America.  Three, S. femoratum  (Say) , S vicarium.  (Walker), and S. terminatum  (Walsh), are common and abundant in the Saskatchewan River system and Boreal streams.  These are very important in the ecological function of the waters because of their biomass and role in the food chain.


            This family contains only one genus, but the history has had numerous changes, the genus  previously being included in Siphlonuridae as well as the Oligonuriidae, and now in a family of its own.  The most unique feature is that larvae  have a double row of long setae on the front legs for filtering algae and organic debris from passing water as they face upstream .   This feature is shared with Lachlania Hagen (Oligonuriidae) but they are only distantly related.

            Isonychia  Eaton  has 16 North American species.  I. campestris  McDunnough is one of the species shared by the Lemsford Ferry community of the South Saskatchewan River and the Colorado river drainage of the southwest, including Utah and New Mexico (shared mayflies  also include Traverella, Choroterpes, Lachlania, Asioplax,  and others).


            This family was formerly a subfamily of Tricorythidae.   Larvae are characterized by operculate gills on segment two, similar to the Caenidae, but in this case the gills are triangular instead of quadrate. 

            Asioplax  Wiersema and McCafferty has 5 North American species, mostly distributed  in the southwest, and the  genus is also associated with South and Central America. The two species known from Saskatchewan, A. corpulenta (Kilgore and Allen) and A. edmundsi  (Allen).  These  may be synonyms.  They are rare and found is the Saskatchewan River at Lemsford Ferry and in the Torch River.

        Tricorythodes Ulmer has 13 North American species. T. minutus  Traver is sometimes common and abundant in prairie rivers and streams, including the Saskatchewan River.


            This Family  has high diversity in the southern hemisphere, but 10 genera are found in North America. Four genera are found in prairie rivers, including two (Traverella Edmunds and Choroterpes Eaton) that are associated with the far southwest US.

            Choroterpes Eaton has  five North American species, and one  (C. albiannulata McDunnough) is abundant at Lemsford Ferry on the South Saskatchewan River.  Adults are found in late in the summer, in August and September, and probably the species has just enough time to complete development before the season cools, and this fits with the species being shared with Utah communities, where warmer waters provide adequate time for development and emergence is much earlier.

            Leptophlebia Westwood can be abundant in slow moving streams and in lakes, and  L. cupida  (Say) and L. nebulosa (Walker) are found in the prairies.  They  may be synonyms since they differ only in  the dark clouds in the wings of the latter,  and the larvae cannot be separated.

            Paraleptophlebia Lestage is a large and distinct genus, the larvae being characterized by distinctly forked gills on the abdomen, and the males having  elaborate penes, often with long reflected spurs and spines.   There are 39 species in North America, and four species, P. adoptiva (McDunnough), P. debilis (Walker) , P. moerens  (McDunnough), and P. praepedita  (Eaton), are common inhabitants of  the clear and unpolluted  streams bordering the prairies. 

            Traverella Edmunds  is another Neotropical genus, like Choroterpes.   T. albertana (McDunnough) is  most reliably collected at Lemsford Ferry on the South Saskatchewan river, and it has connections to the Colorado drainage of the USSW.


            The distribution of members of this family include North America and Eurasia.  Larvae are shaped  like the Baetids, but are much larger,  and are excellent swimmers because of the fish-like shape of the body. Larvae of this family are characterized by bifid fore tarsal claws.

            Metretopus Eaton has two North American species.  The prairie   species, M. borealis  (Eaton) ,  is found in the Palearctic as well as the Saskatchewan River system and boreal streams, giving it an unusual distribution pattern compared to other Saskatchewan species of mayflies.

            Siphloplecton  Clemens is associated with eastern North America.  S. basale (Walker) and S. interlineatum (Walsh) are found in the Saskatchewan River system, and the former, in boreal streams.


            The family is largely tropical, but some species extend northward.  The larvae have a double row of setae on the front legs, rather similar to Isonychia, to filter food particles from the passing water.  Two genera are found in North America, and one is found in Saskatchewan.

            Lachlania Hagen has two species in western North America. L. saskatchewanensis  Ide is found in Mexico and the SWUS, and also in the Saskatchewan River system, especially Lemsford Ferry on the South river.  Previously it was very abundant but recently has been difficult to find, and the reasons are unknown since no conspicuous changes have occurred in the river. Saskatchewan is the type locality for the species (Lehmkuhl 2001).


            This is a small family of burrowing mayflies, with habits and an ecological role similar to the Ephemeridae.

            Ephoron Williamson has two species in North America., and one,   E. album   (Say) is found in large rivers on the prairies.  They are unusual because they are sexually mature as subimagos, and do not moult as adults, a characteristic of all other Ephemeroptera.  In addition, all of the legs are vestigial in females and only the front legs are functional in males, so they must stay in flight during their short lives.  Adults are  usually dead the morning after an evening emergence, forming layers several cm thick under lights at sites along the river.  Larvae burrow in the sediments and are found in great numbers, thus being very important in the ecology of places such as the Saskatchewan River system.

            Tortopus Needham and Murphy is the second genus in the family. T. primus (McDunnough) has been reported from Manitoba but has not been seen for many years.


            The single genus and species in the family has at various times been considered to be part of the Heptageniidae, Ametropodidae, and Siphlonuridae, but now, because of the unique characteristics, it is given a family of its own, .

             Pseudiron McDunnough contains only the species P. centralis McDunnough.  It  was once very abundant in certain parts of the Saskatchewan River system, but recently it has become very hard to find (Lehmkuhl 2001).  Larvae are about 15 mm in length when mature and are predatory.  They have very long laterally placed legs with long claws which can be plunged into the shifting submerged sand substrate and it moves backward, forward, and sidewise where it sweeps for chironomid larvae buried in the sand  It is widespread in the Saskatchewan River system.


            This is the most primitive family of mayflies and the larvae are minnow-like and good swimmers.  Parameletus Bengtsson is found in the prairie region and is represented by 
P. chelifer Bengtsson, which  is Holarctic,  giving it a distribution that is similar to Metretopus borealis.  It is found in the Boreal and not likely to be found in the true prairies.

            Siphlonurus Eaton is the other genus of this family found in the prairies, and S. alternatus   (Say)  is found at the margins of rivers and in lakes where vegetation is abundant, and it  is more associated with the Boreal and mountains  than the prairies.   

Summary comments on Ephemeroptera           

The prairies including the Saskatchewan River system have what is probably the most rich and diverse mayfly fauna of any place in the world, in terms of number of families, number of genera, number of species, and rare species present.  There has been a steady destruction of habitat by dams (Lehmkuhl 1972), sewage Lehmkuhl 1970), and agricultural runoff (personal observations).  Rare and unusual species that were easy to find 25 years ago are now seldom seen, and the reason is not clear.  There has been no special legislation or action taken to save or protect these unique communities (Boyd 2003), and both more research on current status, and special attention to protection needs to be considered.


Edmunds, G.F. Jr. and R.D. Waltz. 1996. Chapter 11. Ephemeroptera. In. Merritt R.W. and K.W. Cummins. Ed. An Introduction to the Aquatic Insects of North America. 3rd Edition. Kendall/Hunt Publishing Co. Dubuque, Iowa.

Edmunds, G.F. Jr., S.L. Steven and L. Berner. 1976. The Mayflies of North and Central America. University of Minnesota Press, Minneapolis.

Lehmkuhl, D.M. 1970. Mayflies in the South Saskatchewan River: pollution indicators. Blue Jay 28:183-186.

Lehmkuhl, D.M. 1976. Mayflies. Blue Jay. 34:70-81.

Webb, J.M. 2002. The mayflies of Saskatchewan. MSc. Thesis. University of Saskatchewan, Sastatoon, Saskatchewan. 430 pp.

See also these and other authors in Selected References

Lehmkuhl D.M. 1968. (*) +
Observations on the life histories of four species of Epeorus in western Oregon (Ephemeroptera: Heptageniidae). // Pan-Pacific Entomol. 44: 129-137.

Lehmkuhl D.M. 1970:183-186. !!
Mayflies in the south Saskatchewan River; pollution indicators. // Blue Jay (Saskatchewan Natural History Society) 28(4): 183-186.

Lehmkuhl D.M. 1970:124-127. +
The life cycle of Rhithrogena morrisoni (Banks) in Western Oregon (Ephemeroptera: Heptageniidae). // Pan-Pacific Entomol. 46(2): 124-127.

Lehmkuhl D.M. 1972. +
(Ephemeroptera: Baetiscidae) from the western interior of Canada with notes on the life cycle. // Canadian Journal of Zoology 50(7): 1015-1017. [97 kb]

Lehmkuhl D.M. 1973:I.Conf.Eph.. +
Adaptations to a marine climate illustrated by Ephemeroptera. // In: Peters W.L. & Peters J.G. (eds). Proceedings of the 1st international conference on Ephemeroptera. E.J. Brill, Leiden: 33-38, 1 pl.  [894 kb]

Lehmkuhl D.M. 1973. (*) +
A new species of Baetis (Ephemeroptera) from ponds in the Canadian arctic, with biological notes. // Canadian Entomologist 105(2): 343-346. Baetis bundyi sp.n.

Lehmkuhl D.M. 1976. (*) +
Additions to the taxonomy, zoogeography and biology of Analetris eximia (Acanthametrepodinae, Siphlonuridae, Ephemeroptera). // Canadian Entomologist 108(2): 199–207. [2.0 Mb]

Lehmkuhl D.M. 1979:675–680. * +
The North American species of Cinygma (Ephemeroptera: Heptageniidae). // Canadian Entomologist 111(6): 675–680.

Lehmkuhl D.M. 1979:859–862. * +
A new genus and species of Heptageniidae (Ephemeroptera) from western Canada. // Canadian Entomologist 111(7): 859–862. Macdunnoa nipawinia gen.sp.n.

Lehmkuhl D.M. 1979:305-308. ?
24. Ephemeroptera. // In: Danks H.V. (ed.). Canada and Insect Fauna. // Mem. Entomol. Soc. Can. 108: 305-308, Table 24.

Lehmkuhl D.M. & Anderson N.H. 1970. +
Observation on the biology of Cinygmula reticulata McDunnough in Oregon (Ephemeroptera: Heptageniidae). // Pan-Pacific Entomologist 46(4): 268-274.

Lehmkuhl D.M. & Anderson N.H. 1971. +
Contribution to the biology and taxonomy of the Paraleptophlebia of Oregon (Ephemeroptera: Leptophlebiidae). // Pan-Pacif. Entomol. 47(2): 85-93.

Lehmkuhl D.M. & Anderson N.H. 1972. !!
Microdistribution and density as factors affecting the downstream drift of mayflies. // Ecology 53: 661-667. [947 kb]