Key to Nearctic and Neotropical species of Triozocera

1. Antefrons triangular; vertex plates clearly separated by post-frons and occiput.................................... 2

- Antefrons rounded anteriorly; vertex plates nearly touching each other anteriorly................................... 4

2. Vertex plates wrapping around eyes and pointed posteriorly near edge of eyes; R 2 vein moderately curved; proctiger (10 th tergite) posterior margin either clearly rounded or straight edged.................................................. 3

- Vertex plates elliptical; R 2 vein straight; proctiger posterior margin mildly curved; total length average for genus (2.8 mm) Mexico, USA .................................................. Triozocera vernalis Kifune and Brailovsky, 1987

3. Inter-eyelet areas covered by densely packed and long trichomes; integument of vertex plates densely dimpled; R 5 vein not branched out from R 4; aedeagus gradually pointed apically; proctiger posterior margin rounded; total length average for genus (ca. 2.8 mm long); Brazil ................................................... Triozocera paulistana Kogan, 1958

- Inter-eyelet area covered by densely packed, very short trichomes (microtrichia); integument of vertex plates smooth, not dimpled; R 5 vein branched out from R 4; aedeagus sharply narrowed from half its length to sharply pointed apex; proctiger posterior margin straight edged; large species (over 3 mm long); Brazil ............................ Triozocera buehrheimi sp. n.

4. Proctiger posterior margin slightly indented medially; R 5 vein not branched out from R 4; total length average for genus (ca. 2.7 mm); Mexico .............................................. Triozocera tecpanensis Brailovsky and Márquez, 1974

- Proctiger posterior margin mildly curved; R 5 vein branched out from R 4; total length mostly below average for genus (ca. 2.6 mm); Cuba, Guatemala, Mexico, Puerto Rico, USA ............................... Triozocera mexicana Pierce, 1909