Key to adult males and females of Udamopyga from Brazil

1. Proclinate orbital setae absent (males)..................................................................... 2

- Proclinate orbital setae present (females)................................................................... 8

2. Juxta wider than long, rounded in lateral and ventral views, with squamous ornamentation (Figs 10–11); vesica with two rounded lobes and inner ventral margin as ladle-shaped projections............ U. squamata Santos & Mello-Patiu sp. nov.

- Juxta longer than wide, rectangular or sub-rectangular in lateral view without squamous ornamentation (Figs 21, 25, 30); vesica with inner ventral margin not as ladle-shaped projections.................................................... 3

3. Three postsutural dorsocentral setae; vesica with conspicuous lateroventral spinose ornamentation and inner ventral margin as two spinose projections (Figs 21–22)......................................................... U. diversa Lopes

- Four postsutural dorsocentral setae; vesica ornamentation and inner ventral margin not as above....................... 4

4. Juxtal lobes with lateral projections (Figs 35–36, 39–40)...................................................... 5

- Juxtal lobes without lateral projections (Figs 25–26, 30–31).................................................... 6

5. Vesica rounded with a central, convex and well-delimited membranous area; juxta with latero-posterior rounded flaps (ventral view) (Figs 3, 35)....................................................................... U. percita (Lopes)

- Vesica rounded, with a poorly-delimited membranous central area; juxtal lobes with latero-anterior membranous projections (Fig. 39).............................................................................. U. provecta (Lopes)

6. Lobe-shaped arms of vesica with striated ornamentation (Figs 4–6, 44–45, 51)................... U. setigena (Enderlein)

- Lobe-shaped arms of vesica with spinose ornamentation or without ornamentation (Figs 25, 30)....................... 7

7. Distal half of cercal prong almost straight in lateral view; juxtal lobes with a concave depression on the distal margin; lobeshaped arms of vesica with spinose ornamentation (Figs 25–26, 47)............................. U. malacophila Lopes

- Distal half of cercal prong slightly curved anteriorly in lateral view; juxtal lobes with a slightly convex dilatation on the distal margin; lobe-shaped arms of vesica without ornamentation (Figs 30–31, 48)........................... U. neivai Lopes

8. T6 with a longitudinal crease along midline dorsally and roof-like appearance (Figs 53–54)........................... 9

- T6 convex along midline dorsally, without a longitudinal crease (Figs 55–56)..................................... 11

9. ST5 as long as wide (Fig. 12).......................................... U. squamata Santos & Mello-Patiu sp. nov.

- ST5 longer than wide................................................................................. 10

10. T6 yellowish-brown, with a well-marked longitudinal crease; epiproct absent (Fig. 53)............. U. malacophila Lopes

- T6 reddish-brown, with a less marked longitudinal crease; epiproct with two pairs of setae (Fig. 54)........ U. neivai Lopes

11. Three postsutural dorsocentral setae.......................................................... U. diversa Lopes

- Four postsutural dorsocentral setae....................................................................... 12

12. T6 with conspicuous golden setulae along posterior margin (Fig. 56).............................. U. provecta (Lopes)

- T6 without golden setulae along posterior margin........................................................... 13

13. T6 opening, i.e., posterior border, forming a concave curve in ventral view; epiproct absent (Fig. 55)..... U. percita (Lopes)

- T6 opening, i.e., posterior border, forming a somewhat sub-quadrangular or inverted U-shaped curve in ventral view; epiproct with two pairs of setae (Fig. 57)........................................................ U. setigena (Enderlein)