Ohio Mayflies

1.         Genae of head capsule completely separated by single rectangular ventral apotome. Only one             species in Ohio. Most abdominal segments dorsally with tuft of 6-8 long setae and/or scale             hairs on each sa2 and sa3 position (Fig. 2.1). (Rare, NE Ohio). . . . . . . . Parapsyche apicalis

            Genae touching ventrally, separating ventral apotome into anterior and posterior parts or                         posterior (Fig. 2.2). Abdominal segments lacking tuft of long setae on sa 2 and sa 3. . . . . . . 2

2.         Posterior ventral apotome much longer than broad, at least half as long as median ecdysial line             where genae touch (Fig. 2.3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

            Posterior ventral apotome no longer than broad, much less than half as long as median ecdysial             line or inconspicuous (Fig. 2.4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.         Pronotum with transverse furrow separating narrower posterior 1/3 from broader anterior                         2/3rds (Fig. 2.4). Two indistinguishable species exist for Ohio; having having a                                     asymetric notch on the left side of the anterior border of the frontoclypeal                                                 apotome. Rare. Homoplectra. . . . . . . . . . . . . . . . . . . . . . . . . . H. doringa or H. monticola

            Pronotum without transverse furrow; constricted only slightly at posterior border (Fig. 2.5). .             . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diplectrona

4.         Head very concave (Fig. 2.6). Abdominal gills each with up to 40 filaments arising fairly                         uniformly along central stalk (Fig. 2.7) foretrochantins never forked. Only one species in Ohio. .             . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Macrostemum zebratum

            Abdomina gills each with about 10 filaments arising mostly near apex of central stalk (Fig. 2.8);             foretrochantins usually forked (Fig. 2.8), sometimes not. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5.         Prosternum with pair of large sclerites in intersegmental fold posterior to prosternal                         plate; (Fig. 2.9); frontclypeus entire (Fig. 2.10). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

            Prosternum with pair of usually small sclerites posterior to prosternal plate (Fig. 2.11);                         if sclerites large, frontoclypeus with shallow mesal excision (Fig. 2.12). . . . . . . . . . . . . . . . . . . 7

6.         Dorsum of abdomen with numerous plain hairs in addition to minute spines on at least first 3             segments, scale hairs present on at least last 3 segments; club hairs absent (use compound             microscope on high power) (Fig. 2.13). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hydropsyche

            Dorsum of abdomen with plain hairs and club hairs only; minute spines and scale hairs absent             (use compound microscope on high power)(Fig. 2.14). . . . . . . . . . . . . . . . . Ceratopsyche*

7.         Anterior ventral apotome of head with prominent anteromedian projection (Fig. 2.15); posterior             margin of each sclerite on abdominal sternum IX entire; lateral border of each mandible                         flanged; foretrochantin forked or not. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Potamyia flava

            Anterior ventral apotome without anteromedian projection (Fig. 2.16); posterior margin of each             sclerite on abdominal sternum IX notched (Fig. 2.17); mandibles not flanged; foretrochantin             forked. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cheumatopsyche sp.**

* Ohio EPA and Midwest Biodiversity Institute continue to use Ceratopsyche at the generic level as do Morse & Holzenthal (2008, In Merritt, Cummings & Berg). Other authors now group it back in Hydropsyche (Schefter, 2005; Geraci, et al., 2010; Armitage, et al. 2011; and, Morse, et al., 2017).

** Ohio EPA carries Cheumatopsyche only to the level of genus. Larvae ofCheumatopsyche have not been classified to species but seven morphotypes (A-G) have been classified largely by virtue of variations of the notch in the frontoclypeus; and, the setae and microscopic spines located on various parts of their body (chaetotaxy)(Burington, 2011). Only 3 of these (A, D & G) have been associated with species found in Ohio (A = C. minuscula; D = C. analis and G = C. campyla). There are 15 species of Cheumatopsyche recognized for Ohio from adults.