Figure above :  Wing-venation of a number of representatives of the family Syrphidae (Brachycera-cyclorrapha).
      Reading from left to right and from top to bottom :
      254 -- Syrphus  ribesii L.
      255 -- Nausigaster  haemorrhoidalis PHIL.
      256 -- Didea  fasciata L.
      257 -- Pipizella  virens FABR.
      258 -- Eumerus  latitarsis MACQ.
      259 -- Volucella  bombylans L.
      260 -- Microdon  devius L.
      261 -- Lathyrophthalmus  aeneus WIED.