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Ephemeroptera: Heptageniidae of Gunnison County, Colorado

Cinygmula par
Hyaline Flat-headed Mayfly

(Eaton) 1885

Updated 18 Dec 2018
TSN 100559


While not reported from Gunnison County yet, it may be present at high elevations, so I started a webpage for it.

Good Links

On this website:
Introduction to Cinygmula

Other Websites:


Eaton,AE 1883-1888 A revisional monograph of recent Ephemeridae or mayflies. Transactions of the Linnean Society of London, Second Series, Zoology 3:1-352, 65 pl.
     Original description of this species from some adult males from Arizona as Cinygma par. [Unfortunately this plate is very faint and I couldn't copy the illustration.]

Edmunds Jr GF. 1952b Studies on the Ephemeroptera Part II. The taxonomy and biology of the mayflies in Utah. PhD Thesis, University of Massachusetts. 399 pages.
     Edmunds described the adults and nymphs. (Quoted from Jensen's thesis) Quote from page 153: "In addition to the possibility of considerable heterozygosity of the genetics of color determination in this species, there seems to be an explanation of the great variablility in this species from the biology and life history. The adults emerge from June to September, the spring brood from cold water being dark and large, while the late summer and fall specimens are lighter and smaller."

Gaufin,AR and Hern,S 1971 Laboratory studies on tolerance of aquatic insects to heated waters. Journal of the Kansas Entomological Society 44:240-245. PDF
     Abstract: "The mature larvae of fifteen species of aquatic insects (Diptera, Ephemeroptera, Plecoptera, and Trichoptera) and the scud (Amphipoda) were tested to determine their relative sensitivity to heated waters under laboratory conditions. The temperature at which 50% died after 96 hours (TLm96) was recorded as the lethal temperature. This ranged from 11.7 C for the torrential stream mayfly, Cinygmula par Eaton, to 32.6 C for the snipefly, Atherix variegata Walker."

Jacobus,LM and McCafferty,WP 2002 Analysis of some historically unfamiliar Canadian mayflies (Ephemeroptera). The Canadian Entomologist, 134(2), pp.141-155. PDF
     Abstract: "Twelve historically unfamiliar Ephemeroptera species described from Canada over 65 years ago were studied. --snip-- Cinygmula confusa (McDunnough, 1924), syn.nov., (Heptageniidae) is shown to be a junior synonym of Cinygmula par (Eaton, 1885), and Serratella serratoides (McDunnough, 1931), syn.nov., (Ephemerellidae) is shown to be a junior synonym of Serratella molita (McDunnough, 1930). --snip-- "

Jensen,SL 1966 The Mayflies of Idaho (Ephemeroptera). M.S. Thesis, University of Utah, Utah. 364 p.
     Quote from page 156-157: "The par-group, of which this species and C. kootenai McDunnough are Idaho representatives, is distinguished in male imagos by the presence of a distinct lateral spine near the base on the ventral surface of each penis. The nymphs of C. par are characteristic in lacking the fibrilliform portion of the gills, and once the nymphs of C. kootenai are known it is believed that they will be similar in this respect. The adults of the two species are, however, easily distinguished by charaters given in the keys.
The nymphs of this species occur in small, cold, swift flowing streams above elevations of 5,000 feet. They are found clinging to the undersides of rocks in the swiftest postions of the current. Adults swarm in the evening over bushes adjacent to the stream during the summer months and in the afternnon later in the fall when the temperatures are too low for evening swarming. They have been collected from June through September.

McCafferty,WP; Durfee,RS; Kondratieff,BC 1993 Colorado mayflies (Ephemeroptera): an annotated inventory. Southwestern Naturalist 38 3, 252-274. PDF
     Quote from page 259-260 "There is considerable confusion about the identification of Cinygmula species mainly due to the fact that larvae have not been adequately described and compared. Cinymula par and Cinygmula mimus seem often to be confused(see previous records above). It remains unclear as to what species the many references to Cinygmula sp. that appear in published ecological studies actually refer. However, C. par is apparently a high altitude species (it was taken by Dodds in headwater areas between 10,500 and 11,650 feet) that has been referred to under various epithets (See also Traver, 1935; Ward and Berner, 1980)."

McCafferty,WP and Provonsha, AV The Mayflies of North AmericaSpecies List (Version 12Jan2009)
     Here is the geographic range and synonyms:
Cinygmula par (Eaton), 1885 [CAN:FN,NW;USA:FN,NW,SW]
* Cinygma confusa McDunnough, 1924 (syn.)
* Cinygma par Eaton, 1885 (orig.)
* Cinygma hyalina McDunnough, 1924 (syn.)
* Cinygmula confusa (McDunnough), 1924 (syn.)
* Cinygmula hyalina (McDunnough), 1924 (syn.)
* Rhithrogena confusa (McDunnough), 1924 (syn.)
* Rhithrogena par (Eaton), 1885 (comb.)

Slater,J and Kondratieff,BC 2004 A review of the mayfly genus Cinygmula McDunnough (Ephemeroptera: Heptageniidae) in Colorado. J. Kansas Entomol. Soc. 77(2): 121-126. PDF

Ward,JV and Berner,L 1980 Abundance and altitudinal distribution of Ephemeroptera in a Rocky Mountain stream. In Advances in Ephemeroptera biology (pp. 169-177). Springer US. PDF

Brown,WS 2005 Ephemeroptera or Mayflies of Gunnison County, Colorado, USA