Key to the extant species of Vianaidinae

1. Hemelytra reduced, coleopteroid........................................................................ 2

- Hemelytra well developed, with a clearly defined membrane, macropterous...................................... 6

2. Body rounded, paranota and costal area of hemelytra widely expanded.......................................... 3

- Body ovate, paranota and costal area of hemelytra narrow, carinated............................................. 4

3. Pronotum anteriorly and paranota punctate; scent gland extending laterally far beyond the hemelytral margin............................................................................................ Thaumamannia vanderdrifti

- Paranota and anterior region of pronotum lacking punctures; scent gland not surpassing hemelytral margin........ T. manni

4. Transverse branch of peritreme connected anteriorly with the longitudinal branch, dividing metapleura in two conspicuously unequal parts........................................................................ Anommatocoris zeteki

- Transverse branch of peritreme connected at the middle of the longitudinal branch, dividing metapleura in two subequal parts.................................................................................................... 5

5. Compound eyes absent, pedicel and basiflagellomere subequal in length............................. A. minutissimus

- Compound eyes with only a few ommatidia, pedicel slightly shorter than basiflagellomere............... A. coleopteratus

6. Macrochaetae absent on head; costal area and subcostal area subequal in width; membrane without outer row of areolae.............................................................................................. A. bolivianus

- Macrochaetae present on head; subcostal area much broader than costal area; membrane with outer row of areolae....... 7

7. Paranota expanded laterally, with three rows of areolae at the widest part......... Pterovianaida duckensis sp. n. (Fig. 1 a)

- Paranota carinate..................................................................... P. melchiori (Fig. 1 b)