Neoperla nebulosa, Stark & Sivec, 2008

Stark, Bill P. & Sivec, Ignac, 2008, New Species And Records Of Neoperla (Plecoptera: Perlidae) From Vietnam, Illiesia 4 (3), pp. 19-54 : 36

Neoperla nebulosa sp. n.

( Figs. 51‐56 , 109‐111 )

Material examined. Holotype ♂ and 13 ♂, 7 ♀ paratypes from Vietnam, Lao Cai, Sapa, large waterfall on road from Sapa to Lai Chau, UV light, 8 May 1995, D. Currie, B. Hubley, J. Swann, ROM 956022 (Holotype ROM, paratypes ROM, IEBR, BPS). Additional paratype: Vietnam: Lao Cai, ca. 12 km on road from Sapa to Lai Chau, 30 April‐12 May 1999, B. Hubley, ROM 992006 , 1 ♀ (pinned, ROM).

Adult habitus. Biocellate. Head with broad dark brown region from occiput to M‐ line; forward of Mline a brown triangular area occurs ( Fig. 51 ). Pronotum brown with darker rugosities; median suture and anterior and posterior margins dark. Wings membranous and veins brown, costa pale in basal third. Femora pale basally but dark in apical half; tibiae brown.

Male. Forewing length 13‐13.5 mm. Tergum 7 process a broadly rounded, elevated plateau. Tergum 8 process tongue shaped, upturned and curved forward. Tergum 9 simple ( Fig. 52 ). Hemitergal processes short and bent laterad at midlength. Aedeagal tube plump and poorly sclerotized except on dorsum; tube armed with minute spines over most of surface ( Fig. 53 ). Aedeagal sac short and trilobed; basoventral portion with a pair of spiny lobes, apical lobe simple but armed on most of surface with spines of various sizes; largest spines clustered near apex and scattered in a lateral patch ( Figs. 53‐54 ).

Female. Forewing length 17‐18 mm. Subgenital plate a short, rounded tab projecting slightly over sternum 9 ( Fig. 55 ). Vagina longer than wide and lined with golden brown scale setae; folds behind spermathecal stalk darker ( Fig. 56 ). Spermathecal stalk short, spermatheca a U‐ shaped sausage with apical hook; accessory gland located in apical third.

Egg. Barrel shaped. Length ca. 0.34 mm, width ca. 0.18 mm, collar width ca. 0.09 mm. Collar sessile and surrounded by 2‐3 irregular rows of scalloped follicle cell impressions ( Figs. 109‐111 ). Striae narrow, wider at midlength, ca. 14 visible in lateral aspect; striae surfaces smooth. Sulci narrower than striae and with three rows of fine punctations visible near poles. Follicle cell impressions on lid with low smooth walls and punctate floors; marginal row with walls more deeply sculpted.

Etymology. The species name refers to the dark appearance of the adults.

Diagnosis. The aedeagus of this species is similar to that of N. spinaloba (described below), N. signatalis Banks and N. quadrata Wu & Claassen. It differs from the former in having a shorter aedeagal sac positioned at an angle to the tube. The sac of N. signatalis is similar in size and shape but the sac armature is relatively more prominent along the ventral margin and reduced along the dorsal margin. In addition, the Taiwanese species is smaller and has a distinctive dark median pronotal band ( Sivec & Zwick 1987). The sac of N. quadrata is more similar to that of N. spinaloba but the tube shares the ventroapical pair of spinulose lobes with all these species.

Figures

Figs. 51‐56. Neoperla nebulosa. 51. Head and pronotum, 52. Male terminalia, 53. Aedeagus, 54. Aedeagal sac, dorsal, 55. Female terminalia, 56. Vagina and spermatheca.

Figs. 106‐111. Egg micrographs. 106. N. mnong. 106. Egg, 107‐108. N. tamdao. 107. Egg, 108. Collar. 109‐111. N. nebulosa. 109. Egg, 110. Collar, 111. Lid.