Identification key to adults of Psylloidea known from Socotra

1 Head rounded down in front, lacking large anterior processes or lobes. ....................... 2

– Head anteriorly bearing large cone-shaped processes or flat lobes. ............................... 3

2 Forewing with common R+M+Cu stem bifurcating into R and M+Cu veins; R S vein medially strongly angulate, curved posteriad and touching M 1+2; membrane with a light brown band along outer posterior wing margin and a small round patch on R 1 apex (Fig. 67). Vertex with two small tubercles on transition to frons; genae with small, apically pointed dorso-lateral projections below antennal insertions (Fig. 68). General body colour in both sexes orange-brown with lighter markings. Generally very small species (FL <1.2 mm). On Commiphora parvifolia and C. planifrons . .................................................. ......... Phacopteronidae: Pseudophacopteron verrucifrons Burckhardt & Harten, 2006

– Forewing with common R+M+Cu stem trifurcating into R, M and Cu veins; R S vein only slightly convex, separated from M 1+2; membrane clear, lacking dark pattern (Fig. 76). Vertex smooth on transition to frons, lacking tubercles; genae rounded below antennal insertions, lacking small pointed projections (Fig. 75). At least males with dark brown to black head and thorax. Generally larger (FL> 1.8 mm). On Ficus vasta . ........................ .................................................................... Triozidae: Pauropsylla jarmilarum sp. nov.

3 Forewing membrane transparent with a yellowish tinge, lacking any dark pattern. Body uniformly light green in alive and dark yellow in dry-mounted or alcohol-preserved specimens (Figs 71, 72). Head with long and slender, nearly symmetrical, conical genal processes (Fig. 73). On Pittosporum viridiflorum . ................. Psyllidae: Cacopsylla sp.

– Forewing membrane semi-transparent to opaque, with a more or less pronounced pattern consisting of numerous brown spots or bands. Body not uniformly light green or yellow. Head different. ................................................................................................................ 4

4 Head with vertex anteriorly produced into flat, apically rounded lobes (Fig. 8), genae small. Forewing pattern consisting of four irregular light brown transverse bands and a couple of small dark brown spots at M 3+4 vein (Figs 1–3, 6–7). Male proctiger apically with long pointed posterior lobes (Fig. 10). On Tamarix nilotica . .................................... .............................................................. Aphalaridae: Colposcenia dioscoridis sp. nov.

– Head with vertex anteriorly straight but genae bearing large, irregularly cone-shaped processes (Figs 22, 43, 48). Forewing pattern different. Male proctiger apically broadly rounded (Figs 27, 49, 56). ( Liviidae: Diaphorina). ...................................................... 5

5 Forewing pattern consisting of dark spots and dark veins not fused into a band along apical wing margin (figured in BURCKHARDT & MIFSUD 1998: 37, Fig. 94). ......... Diaphorina sp.

– Forewing pattern consisting of well-defined dark spots, fusing into a band along apical wing margin. ................................................................................................................... 6

6 Body almost uniformly dark brown (Figs 18–19), generally larger (WL> 2.2 mm). Forewing elongate (WL/WW> 2.5), apically almost symmetrically rounded, with narrow continuous apical dark band (Fig. 20); membrane with coarse surface spinulation (Fig. 21). Head with genal processes approximately as long as vertex along midline, apically subacute (Fig. 22). Antenna relatively elongate (Fig. 32; AL/HW> 0.85). Paramere straight (Figs 27, 28). Female terminalia elongate (Fig. 30, FPL/HW> 1.0). On Carissa spinarum . ....................................................................... Diaphorina caliginosa sp. nov.

– Body lighter brown (Figs 40, 45), generally smaller (WL <1.6 mm). Forewing broader (WL/WW <2.5), apically asymmetrical, with broad continuous apical dark band (Figs 41, 46); membrane with finer surface spinulation (Figs 42, 47). Head with genal processes distinctly shorter than vertex along midline, apically less acute (Figs 43, 48). Antenna relatively robust (Figs 54, 61; AL/HW ≤ 0.85). Paramere apically bent backwards. Female terminalia relatively shorter (Figs 52, 59; FPL/HW <1.0). ........................................... 7

7 Forewing anterior margin in apical portion strongly angulate; forewing pattern consisting of light brown spots basally and darker brown band apically (Figs 39, 41). Male proctiger robust (Fig. 49). Paramere slightly bent apically (Figs 49, 50). On Lycium sokotranum . ............................................................. Diaphorina elegans Burckhardt & Mifsud, 1998

– Forewing anterior margin in apical portion more regularly curved, not angulate; forewing pattern consisting of dark brown spots basally and apical band of same colour (Figs 44, 45). Male proctiger slender (Fig. 56). Paramere strongly bent apically (Figs 56, 57). ..................................................................................... Diaphorina hagherensis sp. nov.