Key of Madeiran Cixiidae based on males

1. Mesonotum with 3 carinae (Figs 4B, 7B, 9B, 10B) ......................................................................... 2

– Mesonotum with 5 carinae (Figs 11B, 12B, 13A) ............................................................................ 5

2. Body length <5 mm; vertex tongue-shaped, posterior margin quadrangular (Fig. 10B); medial carina of frons smooth, reaching the posterior margin of the postclypeus (Fig. 10A); apical margin of tegmina oval with tubercles on the apical margin between the veins (Figs 3E, 10I); first metatarsus with 6 spines distally .............................................................. Tachycixius chaoensis (China, 1938)

– Body length> 5 mm; shape of vertex different, posterior margin concave (Figs 4B, 7B, 9B–D); medial carina of frons distinctively ridged, extending along the frons and the clypeus (Figs 4A, 7A, 9A); apical margin of the tegmina rounded, usually without tubercles on the apical margin between veins, if present they are few (Fig. 5A–C); first metatarsus with 8 spines distally .......................... 3

3. Body length 5.06–5.67 mm; light brown body (Fig. 3A–B); anterior margin of the vertex rounded or slightly acute, slightly concave at the back (Fig. 9B–D); mesonotum light brown; tegmina light golden brown, almost 2 times as long as wide, with small brown setiferous tubercles along the longitudinal veins ................................................................................... C. madeirensis China, 1938

– Body length> 5.90 mm; light blackish to dark brown body; anterior margin of the vertex acute and posterior margin distinctively concave (Fig. 4B, 7B); mesonotum black; tegmina whitish, 2.75 times as long as wide, with large black setiferous points along the longitudinal veins ............................. 4

4. Body length> 7.20 mm. Vertex slightly acute at the anterior margin and concave at posterior margin (Fig. 7B); ventral margin of the aedeagus with a finger-shaped expansion; the largest lateral thorn curves distally forming an angle of 90º; vellum gibbous, without dorsal denticle and the ventral margin distinctively curved distally (Fig. 7K–N) ................................. C. verticalis Noualhier, 1897

– Body length <7.20 mm. Vertex distinctly acute at the anterior margin and tongue-shaped at the posterior margin (Fig. 4B); ventral margin of the aedeagus with a wave-shaped expansion; the larger lateral thorn is curved and does not form a 90º angle distally; vellum subtrapezoid, with a small dorsal denticle and the ventral margin almost straight distally (Fig. 4K–N) .... C. wollastoni sp. nov.

5. Body length> 5 mm; first metatarsus with more than 10 spines. Aedeagus with a long, hook-shaped thorn along the right lateral side and 3 smaller thorns distally on the left side of the aedeagus, two of them much longer (Fig. 13D–E) ....................................... Pentastiridus leporinus (Linnaeus, 1761)

– Body length <5 mm; first metatarsus with less than 10 spines. Aedeagus with two long, thin thorns on the left lateral side (Figs 11I–M, 12I–M) ..................................................................................... 6

6. Vertex often short, lateral margins usually converging anteriorly (Fig. 11B); in lateral view, dorsal thorn of aedeagus wider and longer than the ventral thorn, both converging distally (Fig. 11I–M)... .................................................................................................... H. madeires Remane & Hoch, 1986

– Vertex often long, lateral margins usually parallel (Fig. 12B); in lateral view, dorsal thorn of aedeagus more slender and shorter than the ventral thorn, both distally parallel or divergent (Fig. 12I–M) .... ............................................................................................... H. portonoves Remane & Hoch, 1986