Diura, Billburg, 1820

Nelson, Charles H. & Nelson, C. Riley, 2018, Diura Washingtoniana (Hanson) Resurrected From Synonymy With D. Nanseni (Kempny) (Plecoptera: Perlodidae), Supplemented With A Description Of The Larva And Egg And Comparison To Other Congeners, Illiesia 14 (1), pp. 1-29 : 20-21

Key to the adults of Diura

( D. majuscula not included)

Males

1 Light medial band of tergum 10 complete ( Figs 4 , 33); apical half of paraproct caudal projections in profile appearing somewhat finger-like ( Figs. 5, 6 , 34, 35) ........................................................................... 2

1’ Light medial band of tergum 10 incomplete, mesally interrupted by a darkly sclerotized transverse strip connecting the adjacent tergal halves ( Figs. 48 , 63 ); paraproct caudal projections in profile appearing as a right triangle, apical halves not appearing finger-like ( Figs. 49, 50 , 57, 59, 60 , 64, 65 , 72 ) ………….....................................................….. 3

2 Paraproct caudal projections in profile with apical frontodorsal margins not excavated, terminate in abruptly upturned, slightly bulbous tips that provide a boot-like appearance ( Figs. 5, 6 , 13 , 24 ); tergum 9 with a noticeable mesal patch of sensilla basiconica ( Fig. 4 , 23 ); known distribution northeastern Nearctic realm, New Hampshire and possibly Quebec ………………… D. washingtoniana

2’ Paraproct caudal projections in profile resemble a Bowie knife blade in that the apical frontodorsal margins are noticeably ‘clipped out’ or excavated, terminate in broadly rounded tips that are not bulbous or so sharply upturned as to appear bootlike (Figs. 34, 35, 42, 45, 75); tergum 9 lacks a mesal patch of sensilla basiconica (Figs. 33, 74); known distribution Palearctic realm .................… D. nanseni

3 Paraproct caudal projections in dorsal or ventral view lack a bluntly pointed protuberance at midlength ( Figs. 48, 49, 50, 51 , 56 ); mesothoracic sternum with a complete sternacostal suture separating the basisternum from furcasternum ( Fig. 47 ss); known distribution northern Holarctic ………………............................................. D. bicaudata

3’ Paraproct caudal projections in dorsal or ventral view each with a bluntly pointed protuberance at midlength ( Figs. 63, 65, 66 , 71 ); mesothoracic sternum with an incomplete sternacostal suture ( Fig. 62 ); known distribution higher elevations of western North America………...……… D. knowltoni

Females

1 Spermatheca elongate, somewhat sausage-linkshaped ( Figs. 10 , 39 s), length greater than 2X width ..………………………………………………………...2

1’ Spermatheca ovoid, somewhat egg-shaped ( Figs. 54 , 69 s ), length approximately 1.3X width ..…….…………………………………………………. 3

2 Known distribution eastern Nearctic realm, New Hampshire and possibly Quebec …………… …………………………..…………. D. washingtoniana

2’ Known distribution Palearctic realm. D. nanseni

3 Mesothoracic sternum with a complete sternacostal suture separating the basisternum from furcasternum ( Fig. 47 ss); egg collar ring-shaped and stalked ( Fig. 78 ) …………………… D. bicaudata

3’ Mesothoracic sternum with an incomplete sternacostal suture ( Fig. 62 ); egg collar in dorsal view a Y-shaped triradiate ridge ( Figs. 80, 81 ) ……………………………………….…... D. knowltoni

Figures

Figs. 2–10. Diura washingtoniana, adult. 2. Head and pronotum, dorsal. 3. Mesothorax, ventral. bs = basisternum, fs = furcasternum, ss =sternacostal suture. 4. Male terminalia, dorsal. 5. Male terminalia, lateral. 6. Paraproct caudal projections, lateral and frontal. 7. Paraprocts, ventral. 8. Female terminalia, ventral. 9. Examples of female subgenital plate variation. 10. Spermatheca and vagina. ag = accessory glands, s = spermatheca, sd = spermathecal duct, v = vagina. Scale bars = 0.5 mm.

Figs. 46-54. Diura bicaudata, adult. 46. Head and pronotum, dorsal. 47. Mesothorax, ventral. ss = sternacostal suture. 48. Male terminalia, dorsal. 49. Male terminalia, lateral. 50. Paraproct caudal projections, lateral and frontal. 51. Paraprocts, ventral. 52. Female terminalia, ventral. 53. Examples of female subgenital plate variation. 54. Spermatheca and vagina. ag = accessory glands, s = spermatheca, sd = spermathecal duct, v = vagina. Scale bars = 0.5 mm.

Figs. 61-69. Diura knowltoni, adult. 61. Head and pronotum, dorsal. 62. Mesothorax, ventral. 63. Male terminalia, dorsal. 64. Male terminalia, lateral. 65. Paraproct caudal projections, lateral and frontal. 66. Paraprocts, ventral. 67. Female terminalia, ventral. 68. Examples of female subgenital plate variation. 69. Spermatheca and vagina. ag = accessory glands, s = spermatheca, sd = spermathecal duct, v = vagina. Scale bars = 0.5 mm.

Figs. 55-60. Diura bicaudata adult. 55–58 (Bayan Olgiy, Mongolia). 55. Head and pronotum, dorsal. 56. Male (micropterous) terminalia, dorsal. 57. Male (micropterous) paraprocts, lateral. 58 Female terminalia, ventral. 59. (Arkhangay, Mongolia). Male (macropterous) lateral. 60. (Rhön, Germany). Male (micropterous) paraprocts, lateral.

Figs. 70–73. Diura knowltoni adult (Alberta, Canada). 70. Head and pronotum, dorsal. 71. Male terminalia, dorsal. 72. Male paraprocts lateral. 73. Female terminalia, ventral.

Figs. 11–14. Diura washingoniana adult (Coos County, New Hampshire, USA). 11. Head and pronotum, dorsal. 12. Male terminalia, dorsal. 13. Male paraprocts, lateral, 14. Female terminalia, ventral.

Figs. 23-26. Diura washingtoniana (Coos County, New Hampshire, USA). 23. Adult male tergum 10 with sensilla basiconica, dorsal. 24. Adult male paraprocts, biased lateral. 25. Larval left mandible, ventral. 26. Larval right lacinia, ventral.

Figs. 78-81. 78 Diura bicaudata (Cumberland, England, United Kingdom). Egg collar and anchor, lateral. 79- 81. Diura knowltoni (Summit County, Colorado, USA). 79. Larval pronotal margins, dorsal. 80. Egg, dorsal. 81. Egg collar and anchors, lateral.