Eudactylocladius

Key to male imagines of the subgenus Eudactylocladius

(Modified from Cranston, 1999)

1. Superior volsella well developed, rounded to right­angled........................................................ 2

­ Superior volsella scarcely to moderately developed................................................................... 3

2 Inferior volsella well developed, bluntly triangular; dorsal part of cibarial pump wider than long; no sensilla chaetica on mid leg; Palaearctic .................................... O. (E.) musester sp. n.

­ Inferior volsella weakly indicated to non­existent; dorsal part of cibarial pump not as wide as long; sensilla chaeticae present on mid leg; Palaearctic......................................................................................................................................................................... O. (E.) fuscimanus (Kieffer)

3. Inner margin of gonocoxite with strong dense setae, commencing some distance posterior of gonocoxite base, associated with weakly delimited superior volsella........................................ 4

­ Inner margin of gonocoxite with finer, less dense, setae, commencing closer to gonocoxite base, anterior to sometimes moderately indicated superior volsella........................................... 5

4. Gonostylus without inner projection, squama with 9–14 setae; Nearctic............................................................................................................................................ O. (E.) subletteorum Cranston

­ Gonostylus with inner, preapical, triangular projection; squama with 13–20 setae; Palaearctic. ................................................................................................................ O. (E.) priomixtus sp. n.

5. Superior volsella moderately developed, angular; anal point strong, but not strongly sclerotised, greater than 50 m long; ultimate flagellomere at least 500 m long; Holarctic............... ................................................................................................................... O. (E.) gelidus Kieffer

­ Superior volsella scarcely developed; anal point weak to moderately developed or strong and sclerotised, usually less than 50 m long; ultimate flagellomere often less than 500 m long. 6

6. Anal point strong, well sclerotised; sensilla chaeticae of legs absent; Svalbard..........................

..................................................................................................................... O. (E.) schnelli sp. n. ­ Anal point sometimes very weak to absent, never strongly sclerotised; sensilla chaeticae probably always present on mid and hind legs.................................................................................... 7 7. Gonostylus with microtrichiae on dorsal surface strong and dense, anal point sometimes very weak to absent; Nearctic .................................................................. O. (E.) dubitatus Johannsen

­ Gonostylus with microtrichiae on dorsal surface fine and sparse, anal point well developed.. 8

8. Gonocoxite with both volsellae distinct, particularly the superior; Holarctic......................................................................................................................................... O. (E.) gelidorum (Kieffer)

­ Gonocoxite without differentiated volsellae, just a gently rounded contour; Holarctic.............................................................................................................................. O. (E.) olivaceus Kieffer