Key to Genera of Acanthocephalini *

1. Hind tibiae simple or with tiny expansion.................................................................. 2

- Hind tibiae conspicuously expanded..................................................................... 10

2. Rostral segment IV longer than III; fore, mid, and hind femora in each sex with only one acute subapical spine; humeral angles almost obtuse, with only a tiny expansion (Fig. 23).......................................... Leptopetalops Breddin

- Rostral segment III longer than IV; fore, mid, and hind femora in each sex with one or two rows of acute or stout spines, and always with two large subapical spines; humeral angles expanded, each with a large spine directed outward and backward or with a medium size spine sometimes acute or rounded........................................................ 3

3. Scutellum wider than long; body nearly oval; supracoxal spine present in males; triangular process of pronotum absent or slightly projected (Fig. 13)................................................................. Laminiceps Costa

- Scutellum longer than wide or dimensions subequal; body elongate; supracoxal spine present or absent in males; triangular process of pronotum visible or absent..................................................................... 4

4. Humeral angles obtuse, slightly angulate; supracoxal spine in males absent; body surface with bluish-green metallic reflections (Fig. 19)......................................................................... Ctenomelynthus Breddin

- Humeral angles expanded, with a medium size to clearly elongate spine, acute, directed outward and backward; supracoxal spine in males present or absent; body surface with or without bluish-green reflections.............................. 5

5. Metapleural supracoxal spine in males present.............................................................. 6

- Metapleural supracoxal spine in males absent............................................................... 7

6. Rostral segment III longer than II; humeral angles conspicuously produced into sharp spines directed outward and slightly backward (Figs. 21, 33–36)........................................................ Petalops Amyot & Serville

- Rostral segment II longer than III; humeral angles produced into a medium size spine, directed outward and slightly backward (Fig. 24)................................................................................... Salapia Stål

7. Head and pronotum densely clothed with erect hairs; male hind femora without short, acute basal spine................. 8

- Head and pronotum glabrous or with few scattered hairs; male hind femora with short, acute basal spine................ 9

8. Antenna shorter than total body length; hind femora in both sexes moderately robust; hind tibiae in males with small spines, in females unarmed (Fig. 14).......................................................... Cleotopetalops Brailovsky

- Antennae longer than total body length; hind femora in both sexes conspicuously incrassate (slightly less in females); hind tibiae in males armed with one row of large and stout spines (unarmed in females) (Figs. 4–5)....... Antipetalops gen. nov.

9. Male hind acetabulae with large, broad, creamy yellow hardened protuberance; tylus in lateral view conspicuously expanded, resembling a foliate-shape; rostrum reaching to middle third of metasternum (Figs. 7–9).......... Cryptopetalops gen. nov.

- Male hind acetabulae without creamy yellow, hardened protuberance; tylus in lateral view not prominently projected, triangular; rostrum reaching posterior border of mesosternum (Figs. 1–3)............................. Anomalopetalops gen. nov.

10. Dorsal surface of male connexival segments V–VII covered with small acute to stout spines or tubercles, intermixed with large and robust expansion................................................................................. 11

- Male and female connexival segments V–VII without spines or tubercles along the upper surface..................... 13

11. Metathoracic scent gland opening with two fused auricles resembling an unilobed structure; mesopleuron without creamy yellow hardened spots; hind tibiae longer than the maximum length of abdomen; antennal segments IV longer than II and III together (Figs. 18, 22)....................................................... Stenometapodus Breddin (in part)

- Metathoracic scent gland auricle bilobate; mesopleuron with one or two creamy yellow hardened spots; hind tibiae longer or shorter than maximal length of abdomen; antennal segment IV longer or shorter than II and III together................ 12

12 Antennal segment IV longer than II and III together; hind tibiae longer than maximal length of abdomen; apex of scutellum globose with hardened prominent creamy yellow callosity; mesopleuron with one or two creamy yellow hardened callosities (Fig. 11)............................................................ Ichilocoris Brailovsky & Barrera (in part)

- Antennal segment IV shorter than II and III together; hind tibiae shorter or subequal to the maximal length of abdomen; apex of scutellum creamy yellow to yellowish orange, slightly raised above scutellar disk; mesopleuron without one or two creamy yellow hardened callosities (Fig. 15).................................. Cervantistellus Brailovsky & Barrera (in part)

13. Posterior angles of abdominal segments V and VI spined..................................................... 14

- Posterior angles of abdominal segments V and VI not spined.................................................. 19

14. Pronotal disc tuberculate, impunctate (Fig. 16).................................................. Empedocles Stål

- Pronotal disc punctate, without tubercles.................................................................. 15

15. Hind tibiae shorter than maximal length of abdomen; outer expansion of hind tibiae lanceolate....................... 16

- Hind tibiae longer than maximal length of abdomen; outer expansion of hind tibiae uniformly narrowed............... 17

16. Triangular process absent; scutellar disc lacking erect setae; anterior third of anterolateral margins of pronotum covered with small blunt spines close to frontal angles; mesopleuron without creamy yellow callosities; rostral segment IV subequal to III (Fig. 20)........................................................................ Meluchopetalops Breddin

- Triangular process present; scutellar disc with erect setae; entire anterolateral margins of pronotum irregularly nodulose and with blunt spines; mesopleuron with one or two creamy yellow callosities; rostral segment IV shorter than III (Fig. 15).................................................................... Cervantistellus Brailovsky & Barrera (in part)

17. Metathoracic scent gland opening with two fused auricles resembling an unilobed or single structure (Figs. 18, 22).................................................................................. Stenometapodus Breddin (in part)

- Metathoracic scent gland auricle bilobate................................................................. 18

18. Triangular process present; mesopleuron with one or two creamy yellow hardened callosities (Fig. 11)...................................................................................... Ichilocoris Brailovsky & Barrera (in part)

- Triangular process absent; mesopleuron without creamy yellow hardened callosities (Fig. 6)..... Zygometapodus Brailovsky

19. Outer expansion of hind tibiae straight, narrow, without spines; antennal segments II and III together shorter than IV (Fig. 10).......................................................................................... Lucullia Stål

- Outer expansion of hind tibiae not straight, wide, either sinuate or spinated; antennal segments II and III together longer than IV ................................................................................................ 20

20. Rostral segments III and IV together longer than II (Fig. 17)................................ Acanthocephala Laporte

- Rostral segments III and IV together shorter than II (Fig. 12)......................................... Thymetus Stål