Cyclolabus Heinrich, 1935

Cyclolabus Heinrich, 1935: 198 .

Type species: Platylabus nigricollis Wesmael, 1845 by original designation.

Comparative diagnosis

From all the other four Nearctic Platylabini genera with small circular or roundish propodeal spiracles – Apaeleticus, Carlsonia, Cyclolabus and Linycus – Cyclolabus can be easily distinguished by: the strongly pronounced gastrocoeli; thryidia larger than the space between them; and the presence of distinct propodeal carinae (Figure 10). Cyclolabus is also morphologically similar to Platylabus Wesmael, 1845, mainly differing from it by the presence of small and circular propodeal spiracles (Figure 22) (Heinrich 1961, 1962b; Tereshkin 2009). However, as already noted by Heinrich (1962b), the small species of Platylabus can also possess roundish and relatively small spiracles, rendering the demarcation of the two genera ambiguous for certain specimens. In these latter cases, the observation of other characters is necessary, and we have listed them under the genus Platylabus .

Range and diversity

Cyclolabus has a worldwide distribution, with 11 species in the Nearctic and only two species occurring in the south-eastern United States (Heinrich 1961, 1962b; Yu et al. 2016).

Key to the species of Cyclolabus from the south-eastern United States (adapted from Heinrich (1962b))

1. Scutellum and mesoscutum ferruginous (Figures 13a–13e); pronotal ridge ferruginous (Figure 13a); inner orbit ferruginous or light ferruginous (Figure 13c)................... ........................................................................... gracilicornis gracilicornis (Provancher, 1886)

- Scutellum yellowish white, mesoscutum ferruginous (Figure 11a); pronotal ridge yellowish white (Figure 11a); entire face yellowish white (Figure 11c).............................. ............................................................................................................. carolinensis (Heinrich, 1962)