I. Adult key to eastern Nearctic Nemourinae genera

(modified from Baumann 1975 and Stewart & Stark 2008)

1 Males .............................................................................................. 2

- Females............................................................................................. 9

2 Cervical gills present, either unbranched or 4-branched (Figs. 159, 163); wing venation typical for family (Fig. 8).... Zapada

- Cervical gills absent; wing venation variable (Figs. 1, 3, 7).................................................... 3

3 Veins A 1 and A 2 of forewing joined near posterior margin (Fig. 7); epiproct either slightly (Fig. 105) or markedly bilaterally asymmetric (Fig. 115)............................................................................ Soyedina

- Veins A 1 and A 2 of forewing not joined (Figs. 1‒6); epiproct bilaterally symmetric (Figs. 31, 44, 61)................... 4

4 Vesicle absent from sternum 9; terminal costal crossvein of forewing joins Sc vein before junction with R vein, typical “X” pattern at cord absent (Fig. 3).................................................................. Paranemoura

- Vesicle present on sternum 9; terminal costal crossvein of forewing joins R vein, typical “X” pattern at cord present (Figs. 1‒2, 4‒6)................................................................................................ 5

5 Cerci sclerotized and developed, either with lateral spines (Figs. 10‒12) or elongated and recurved (Figs. 37‒38)......... 6

- Cerci simple and unmodified (Figs. 51, 86)................................................................. 7

6 Cerci robust with paired appressed spines (= as; Figs. 9‒13) and one outer spine (= os), the latter may be apically forked (Fig. 13) or not (Figs. 12)............................................................................ Nemoura

- Cerci elongated and medially arcuate, apically pointed or bifurcated (Figs. 19, 25, 31, 37).................... Ostrocerca

7 10 th tergum enlarged at lateral proximal corners into long, sclerotized spiny lobes (Figs. 95‒96)................... Shipsa

- 10 th tergum unmodified at lateral proximal corners (Figs. 45, 161)............................................... 8

8 Epiproct long and narrow throughout length, comprised mainly of the ventral sclerite, (Figs. 61, 69, 77, 85); dorsal sclerite reduced to lateral arms (Figs. 67, 82, 88) or essentially absent (Fig. 74)..................................... Prostoia

- Epiproct short and robust, ventral sclerite T-shaped and expanded laterally (Figs. 56‒57); dorsal sclerite prominent and terminates as bifurcated lateral arms (Figs. 57‒58).................................................... Podmosta

9 Cervical gills present, either unbranched or 4-branched (Figs. 155, 159) wing venation typical for family (Fig. 8).... Zapada

- Cervical gills absent; wing venation variable (Figs. 1, 3, 7) ... 10

10. Veins A 1 and A 2 of forewing joined near posterior margin (Fig. 7)......................................... Soyedina

- Veins A 1 and A 2 of forewing not joined (Figs. 1‒6).......................................................... 11

11 7 th sternum covering at least ¾ of 8 th sternum (Figs. 17‒18)............................................. Nemoura

- 7 th sternum less produced, covering <½ of 8 th sternum (Figs. 23, 75, 98)......................................... 12

12 Terminal costal crossvein of forewing joins Sc vein before junction with R vein, typical “X” pattern at cord absent (Fig. 3)......................................................................................... .. Paranemoura

- Terminal costal crossvein of forewing joins R vein, typical “X” pattern at cord present (Fig. 1‒2, 4‒6)................. 13

13 8 th sternum enlarged and modified as subgenital plate; 7 th sternum with a medial, nipple-like projection (Figs. 24, 30, 35) (except O. truncata, Fig. 42).................................................................... Ostrocerca

- 8 th sternum not enlarged, only as medial subgenital plate or medial sclerotized pattern; 7 th sternum without medial, nipple-like projection (Figs. 60, 84, 98)............................................................................ 14

14 Subgenital plate apex broad, encompassing at least 50% of the total width of the 8 th sternum, varying from scarcely (Figs. 68, 84) to moderately (Figs. 75, 93) emarginate medially................................................... Prostoia

- Subgenital plate apex comparatively smaller, encompassing much less than 50% of the total width of the 8 th sternum (Figs. 60, 98)................................................................................................ 15

15 Subgenital plate with a distinct medial notch (Fig. 59‒60).............................................. Podmosta

- Subgenital plate lacking a distinct medial notch, rounded distally (Fig. 98).................................... Shipsa