Cyclocephalini, Castelnau, 1840

Rodrigues, Sérgio Roberto, Barbosa, Carlos Aparecido Ferreira, Fuhrmann, Juares & Amaro, Ricardo Aparecido, 2018, Mating behavior and description of immature stages of Cyclocephala melanocephala (Fabricius, 1775) (Coleoptera: Scarabaeidae: Dynastinae), identification key and remarks on known immatures of Cyclocephalini species, Revista Brasileira de Entomologia 62 (3), pp. 205-219 : 214

Key to known third instar larvae of known Cyclocephalini (minute setae are omitted in the key)

1 – Antennomere IV with one or more than 2 dorsal sensorial spots; zygum as a cross-bar or beak-like with 1 or more than 2 teeth; abdominal tergites VIII–IX with or without numerous small stout setae............................................................................................... Dynastinae other than Cyclocephalini

1 Ɩ – Antennomere IV with 2 dorsal sensorial spots; zygum beak-like with 0 or 2 teeth; abdominal tergites VIII–IX without small stout setae...... Cyclocephalini ....... 2

2(1) – Head without anterofrontal setae (afs); zygum toothless and with posterior margin crenulate or straight; left mandible with fourth scissor tooth (S4 present)...................................................................................................................................................................... 3

2 Ɩ – Each head side with 0–2 anterofrontal setae (afs); zygum 2-toothed; left mandible with or without S4.... Cyclocephala Dejean, 1821 (part)......................... 7

3(2) – Head without posterofrontal setae (pfs); perforations of thoracic spiracle ameboid and bearing more than 4 sinuosities.............. Ancognatha manca LeConte, 1866

3 Ɩ – Each head side with 1–2 posterofrontal setae (pfs); perforations of thoracic spiracle oblong, if perforations slightly irregular shaped, then them with less than 4 sinuosities................................................................................................................................................................... 4

4(3) – Each head side with 1 anterofrontal angle seta (aas)......... C. fasciolata Bates, 1888

4 Ɩ – Each head side with 2–4 anterofrontal angle setae (aas)....... Dyscinetus Harold, 1869 .................................................................................. 5

5(4) – Each head side with 4–5 dorsoepicranial setae (des)..................................................................................... D. morator (Fabricius, 1798)

5 Ɩ – Each head side with 2 dorsoepicranial setae (des)....................................................................................................................... 6

6(5) – Each side with 3–4 anterofrontal angle seta (aas); haptolachus left side with about 18 setae.............................................. D. dubius (Olivier, 1789)

6 Ɩ – Each head side with 2 anterofrontal angle seta (aas); haptolachus left side with less than 10 setae.................................. D. rugifrons (Burmeister, 1847)

7(2) – Palidia present, sometimes pali irregularly distributed and septula barely distinct, but pali even easily differentiated from tegillar setae....................... 8

7 Ɩ – Palidia absent............................................................................................................................................................ 11

8(7) – Each palidium with more than 30 setae.................................................................................................. C. testacea Burmeister, 1847

8 Ɩ – Each palidium with less than 10 setae................................................................................................................................... 9

9(8) – Each palidium with 6–8 acute setae...................................................................................................... C. modesta Burmeister, 1847

9 Ɩ – Each palidium with 3–4 bifurcate setae ( Fig. 44a)...................................................................................................................... 10

10(9) – Each head side with 2–3 posterofrontal setae (pfs), 2 anterofrontal setae (afs), 2–3 posterolabral setae (pls).................................. C. melanocephala (Fabricius, 1775)

10 Ɩ – Each head side with 1 posterofrontal seta (pfs), 1 anterofrontal seta (afs), 1 posterolabral seta (pls)................................... C. paraguayensis Arrow, 1913

11(7) – Left mandible with S4........................................................................................................................ C. jalapensis Casey, 1915

11 Ɩ – Left mandible without S4............................................................................................................................................... 12

12(11) – Ventral anal lobe with 7–9 posteromedial hamate setae twice larger than other hamate setae (cf. Remedi-de-Gavotto, 1964: Fig. 8 ; Pereira and Salvadori, 2006: Fig. 6b ).............................................................................. C. flavipennis Arrow, 1914 and C. signaticollis Burmeister, 1847 (see remarks)

12 Ɩ – Ventral anal lobe with medial setae not or slightly bigger than lateral setae OR setae progressively larger to medial area, but setae enlargement never abrupt... 13

13(12) – Abdominal spiracle I evidently smaller than II–V................................................................................................................. 14

13 Ɩ – Abdominal spiracle I–V with similar size.............................................................................................................................. 17

14(13) – Each head side with more than 6 dorsoepicranial setae (des)............................................................................. C. longula LeConte, 1863

14 Ɩ – Each head side with less than 5 dorsoepicranial setae (des)........................................................................................................... 15

15(14) – Each head side with 1 dorsoepicranial seta (des) and 1 posteroepicranial seta (pes)....................................... C. gregaria Heyne & Taschenberg, 1908

15 Ɩ – Each head side with 2–4 dorsoepicranial setae (des) and 5–6 posteroepicranial setae (pes)......................................................................... 16

16(15) – Maxillary stridulatory area with 7 teeth and an anterior truncate process............................................................ C. lunulata Burmeister, 1847

16 Ɩ – Maxillary stridulatory area with 9–10 teeth and an anterior truncate process.......................................................... C. fulgurata Burmeister, 1847

17(13) – Ventral anal lobe with more than 45 hamate setae............................................................................................................... 18

17 Ɩ – Ventral anal lobe with less than 40 hamate setae...................................................................................................................... 19

18(17) – Each head side with 2 dorsoepicranial setae (des), 2 posteroepicranial (pes) and without anterofrontal setae (afs)............................................ C. comata Bates, 1888

18 Ɩ – Each head side with 3–4 dorsoepicranial setae (des), 3 posteroepicranial (pes) and 1–2 anterofrontal setae (afs).......................... C. sinaloae Howden & Endrödi, 1966

19(17) – Each side of raster with 7–9 hamate setae............................................................................................. C. distincta Burmeister, 1847

19 Ɩ – Each side of raster with more than 10 hamate setae................................................................................................................... 20

20(19) – Each side of raster with less than 17 hamate setae................................................................................................................ 21

20 Ɩ – Each side of raster with more than 18 hamate setae................................................................................................................... 23

21(20) – Maxillary stridulatory area with 4 teeth and an anterior truncate process.............................................................. C. celata Dechambre, 1980

21 Ɩ – Maxillary stridulatory area with more than 6 teeth and an anterior truncate process............................................................................... 22

22(21) – Abdominal tergite X with a U-shaped thin sclerotized bar (similar to Figs. 5 , 14), area anterior to sclerome with a transversal setae group................... C. lurida Bland, 1863

22 Ɩ – Abdominal tergite X with a U-shaped thin sclerotized bar, area anterior to sclerome bare................................................ C. pasadenae (Casey, 1915)

23(20) – Ventral anal lobe with about 20 hamate setae.......................................................................................... C. barrerai Martínez, 1969

23 Ɩ – Ventral anal lobe with about 30 hamate setae................................................................................................... C. borealis Arrow, 1911

Figures

Figs. 7–12. Cyclocephala melanocephala, third instar larva; 7, cranium and clypeus,dorsal; 8, labrum, dorsal (epipharyngeal ventral setae omitted); 9–12, left antenna (dorsal, internal, external, ventral; external and internal sides with apex detail; some sensilla numbered to easily the correspondence; sensillum h can be absent).Chaetotaxy (italic) on the text. Scale= 0.5mm (antennal details with magnification four times bigger than antennae).

Figs. 5–6. Cyclocephala melanocephala, third instar larva; 5, lateral; 6, head, dorsal. t10, abdominal tergite X; usb, U-shaped sclerotized bar. Scale= 1 mm.