Flavoperla pallida, Stark & Sivec, 2008

Stark, Bill P. & Sivec, Ignac, 2008, New Vietnamese Species Of The Genus Flavoperla Chu (Plecoptera: Perlidae), Illiesia 4 (5), pp. 59-65 : 62-64

Flavoperla pallida sp. n.

( Figs. 11‐16 , 20‐22 )

Material examined. Holotype ♂ and ♀ paratype from Vietnam, Lao Cai, Sapa, large waterfall on road from Sapa to Lai Chau, UV light, 8 May 1995, ROM 956022 , D. Currie, B. Hubley, J. Swann ( ROM) .

Adult habitus. Biocellate. General color pale yellow. Head with indistinct pale brown area forward of Mline and on lappets ( Fig. 11 ). Pronotum with dark margins and obscure pale brown rugosities on disc. Wings transparent, veins pale.

Male. Forewing length 9 mm. Epiproct sclerite about as long as wide, mostly sclerotized, but with small anterior membranous notch ( Fig. 12 ); anterior margin set between bases of paired spines. Paraprocts broad, upright and without apical hook. Hammer apex unpigmented, triangular and somewhat oval in lateral aspect ( Figs. 13‐14 ). Aedeagus not everted, but Fig. 16 shows the dorsal aspect in contracted position.

Female. Forewing length 13 mm. Subgenital plate shield shaped, with small mesal point approaching posterior margin of sternum 9 ( Fig. 15 ). Mesal field of sternum 9 with a broad, shallow membranous area; membrane of notch covered with fine, linear microtrichia.

Egg. Spindle shaped, lid pointed ( Fig. 22 ). Collar absent ( Fig. 20 ), anchor medusoid (removed in Fig. 20 ). Chorion finely punctate throughout; opercular line present but indistinct; lid covered with follicle cell impressions which enclose ca. 40 punctations. Micropyles simple ( Fig. 21 ).

Larva. Unknown.

Etymology. The name refers to the pale pigmentation of this species.

Diagnosis. Flavoperla dao is similar to F. hmong in paraproct structure, but the latter species is distinguished on the basis of the dark ocellar patch ( Fig. 6 ), a wider and completely sclerotized epiproct ( Fig. 7 ), and by the upturned apex of the hammer ( Fig. 9 ) as seen in lateral aspect. The color pattern ( Fig. 1 ) and hammer shape ( Fig. 4 ) of F. dao are more similar to F. pallida ( Figs. 11, 14 ) but that species has broader, more triangular paraprocts ( Fig. 12 ) which are more upright and lack an apical curved point. Females of the three species are also similar, but subtle differences occur in shape of the subgenital plate and in sternum 9. Flavoperla pallida is distinctive by virtue of the mesoapical point on the subgenital plate ( Fig. 15 ), whereas the other two species have broadly rounded plates ( Figs. 5 , 10 ). Flavoperla hmong can be distinguished from F. dao by the faint transverse line which crosses the subgenital plate near the plate base ( Fig. 10 ). Eggs of the three species are very similar but those of F. pallida have a more pointed lid than the eggs of the other species. Unfortunately, no comparisons can be made between these three species from Vietnam and their Chinese congeners until fresh specimens are available. The following key is offered to assist in distinguishing adults of these three species.

Figures

Figs. 11‐16. Flavoperla pallida. 11. Head and pronotum, 12. Male terminalia, dorsal, 13. Male sternum 9, 14. Male segment 9, lateral, 15. Female terminalia, 16. Uneverted male aedeagus, dorsal aspect in situ.

Figs. 17‐22. Flavoperla eggs. 17‐19. F. hmong. 17. Collar region with anchor (finger lobes broken), 18. Subequatorial region of chorion with micropyle, 19. Operculum and lid. 20‐22. F. pallida. 20. Collar region, anchor removed, 21. Subequatorial region of chorion with micropyle, 22. Operculum and lid.

Figs. 6‐10. Flavoperla hmong. 6. Head and pronotum. 7. Male terminalia, dorsal. 8. Male sternum 9. 9. Male segment 9, lateral. 10. Female terminalia.

Figs. 1‐5. Flavoperla dao. 1. Head and pronotum, 2. Male terminalia, dorsal, 3. Male sternum 9, 4. Male segment 9, lateral, 5. Female terminalia.