Key to the Macaronesian species and subspecies of Phaonia Robineau-Desvoidy

1 Abdomen yellow, sometimes dark mid-dorsally. Notopleuron without setulae...................................... 2

- Abdomen wholly dark. Notopleuron with setulae............................................................ 3

2 Antenna yellow, darkened on distal part of postpedicel. Thorax yellow to dark amber coloured, without dark striping on mesonotum. Radial node ventrally with a few setulae.................................. 7. Phaonia pallida (Fabricius)

- Antenna fuscous brown to black. Thorax dark with yellow postpronotal calli and scutellum, with distinct dark striping on mesonotum. Radial node bare..................................................... 6. Phaonia subventa (Harris)

3 Longest aristal branches subequal to width of postpedicel. Presutural acrostichal field with 2 pairs of setae among fine ground setulae. Notopleuron with setulae confined to posterior half. Meron with 0–5 setulae beneath spiracle.................. 4

- Longest aristal branches 1.5 times as long as width of postpedicel. Presutural acrostichal field with ground setulae only. Notopleuron with setulae on both halves. Meron bare......................................................... 6

4 Mesonotum and abdomen with dense greyish pruinosity disclosing a dark pattern of four stripes on mesonotum and a dorsal stripe on abdomen. Fore tibia with 1–2 p setae.............................................................. 5

- Mesonotum and abdomen with usual striping pattern obsolete, appearing shiny bluish black through a sparse layer of light bluish grey pruinosity. Fore tibia without p seta(e).................................... 5. Phaonia nigrisquama Stein

5 Scutellum translucent yellow on distal part. Body covered in light greyish pruinosity. Calypteres whitish, much paler than light brownish wing base................................................ 3. Phaonia trimaculata trimaculata (Bouché)

- Scutellum wholly dark. Body covered in dark grey pruinosity with a distinct bluish tinge. Calypteres dark grey with blackish margins, concolorous with wing base....................................4. Phaonia trimaculata sordidisquama Stein

6 Calypteres creamy to ochre yellow. Pruinosity of thorax and abdomen similar, brownish grey. Both thoracic spiracles with yellow fringes. Legs with yellow tibiae and yellow to ochre brown middle and hind femora........................................................................................... 1. Phaonia tuguriorum tuguriorum (Scopoli)

- Calypteres brownish to greyish black. Pruinosity of abdomen with a bluish tinge set off from the brownish grey thorax. Posterior spiracle with a brown fringe. Legs extensively brownish black, only more or less translucent ochre brown on femora and tibiae of middle and hind legs............................................ 2. Phaonia tuguriorum canariensis Villeneuve