Microibidion

Key to species of Microibidion

1. Elytral apex with outer angle distinctly projected............................................................ 2

- Elytral apex with outer angle not projected................................................................ 3

2(1). Prothorax distinctly narrower basally than apically. Brazil (Bahia, Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul), Paraguay, Argentina (Misiones, Corrientes)........ M. exiguum Martins, 1962

- Basal and distal width of prothorax similar. Brazil (Bahia, Rio de Janeiro)................. M. fluminense (Martins, 1962)

3(1). Elytra with basal half reddish and distal half black, separated by transverse yellowish region. Argentina .......................................................................................... M. rubicundulum (Gounelle, 1913)

- Elytra with different color pattern.........................................................................4

4(3). Elytra with 3 yellowish-white maculae. French Guiana ................................. M. kawensis Audureau, 2015

- Elytra, at most, with 2 yellowish or whitish maculae..........................................................5

5(4). Prothorax uniformly rounded laterally, without distinct basal constriction. Brazil (Espírito Santo, Rio de Janeiro, Santa Catar- ina)........................................................................... M. muticum (Martins, 1962)

- Prothorax with distinct basal constriction, subparallel-sided from constriction to distal margin........................ 6

6(5). Antennomeres III–IV without long and erect setae along ventral side; elytra with erect setae distinctly sparse and short (Fig. 7). Paraguay ................................................................. M. bimaculatum Mehl et al., 2015

- Antennomeres III–IV with long and erect setae along ventral side; elytra with erect setae long and moderately abundant (Figs. 5, 8)............................................................................................... 7

7(6). Metasternum impunctate laterally (Fig. 10). Bolivia, Peru, Argentina (Jujuy).................. M. mimicum Martins, 1971

- Metasternum punctate laterally (Fig. 9)................................................................... 8

8(7). Antennae entirely reddish-brown; elytra with transverse and moderately narrow yellowish band at about midlength; mesofem- oral club slender (Fig. 6). Brazil (São Paulo, Rio Grande do Sul), Paraguay, Argentina (Misiones, Buenos Aires)......................................................................................... M. exculptum Martins, 1962

- Antennae dark brown, mainly on basal segments; elytra with large, irregular yellowish band covering about midlength of basal half and part of distal half; mesofemoral club thicker (Figs. 1–3). Bolivia .......................... M. morrisi sp. nov.