Vol 2 Part 2a. Hemiptera - Cicadomorpha - Royal Entomological ...

BA'l'RACOMORPJIUS, IASSUS, ONCOPSIS 35Genus Oncopsis Burmeister( = Bythoscopus : auctt. nee Germar)Some of the problems of this genus have been discussed by Wagner(1949) and Le Quesne (1961b) ; the latter showed that 0 . subangulata isprobably a distinct species from flavicollis and this view is supported byHalkka (1959), who has shown chromosomal differences between them.0. avellanae Edwards is here regarded as an ecological form of carpiniSahlberg. On this basis, we have in Britain five out of the seven WesternEuropean species.It has been found more convenient to provide separate keys forthe males and females.1KEY TO SPECIES(Males)Length of fore wing 3·4-3·6 mm. ; a more or less rounded brown spot on 11'lrl)Ucross-vein (fig. 167). (Face yellow-brown, with black thyridia and dark interocular- band reaching eyes ; discoidal cross-band more or less strongly marked, discoidalspots usually light brownish or absent ; postocellar spots often present ; medianband absent. On vertex, narrow light brown band usually present posterior tointerocular band. Pronotum grey-brown with blackish dots along striations.Scutellum chestnut-brown, often with darker basal triangles and sometimesdarker longitudinal median streak or suffused darker apically. Fore wingslightly smoky hyaline with veins and corio-claval suture narrowly black-brown,usually with some dark suffusion around margins of apical cells, at apex of coriaclavalsuture and along inner margin between apices of first and second apicalveins. Legs brownish with a dark line along outer margin of tibiae. Outersurface of aedeagus convex (fig. 199); paramere narrow at apex, withoutdistinct lamella (fig. 181); aedeagus basal supports similar to those of jlavicollis(figs. 196-198).Overall length 3·9-4·4 mm.)( = rujuscula (Fieber)) tristis (Zetterstedt)On Betula (birch). England. Wales. Scotland. Ireland. vi-ix. Europe.Siberia.- Length offore wing greater than 3·6 mm.; 11'lrl)U cross-vein normally narrowly ornot at all bordered darker (figs. 157, 162) ............. . .................... 22 Scutellum usually largely black or blackish, with bright yellow spots along sidestowards apex;- a broad dark patch almost always present towards the apexbetween the yellow markings (figs. 168, 169). Veins of fore wing nigger-brown toblack, cells hyaline except often for a dark brownish suffusion in the apical cells (atleast near veins), on either side of m--