Osmodes adon Mabille, 1890

Cock, Matthew J. W., Congdon, T. Colin E. & Collins, Steve C., 2016, Observations on the biology of Afrotropical Hesperiidae (Lepidoptera). Part 9. Hesperiinae incertae sedis: Zingiberales feeders, genera of unknown biology and an overview of the Hesperiinae incertae sedis, Zootaxa 4066 (3), pp. 201-247 : 228-231

Osmodes adon Mabille, 1890

This is a rare forest butterfly described from Sierra Leone, and with scattered records from there east to Cameroon and Zaire ( Ackery et al. 1995, Larsen 2005). Females are difficult to identify with confidence. MJWC reared a single female ( Figure 32 ) from Forêt du Yapo, Côte d’Ivoire, which is provisionally allocated to O. adon , following a discussion with T.B. Larsen (pers. comm. 2014). The choice was between O. distincta Holland and O. adon , but we think this is more likely to be O. adon as the cell spots are less segregated from the discal spots and the lack of light shading between the unh margin and the discal spots; also, in O. distincta the discal spot in 3 upf does not reach the base of the cell.

1This record may refer to O. lindseyi Miller ( Larsen 2005) ; it is unlikely to be O. adosus which is not recorded from Uganda.

MJWC collected a prepupa on Sarcophrynium brachystachys (Marantaceae) (MJWC 316), 3 June 1989 (MJWC 89/214). The leaf shelter was made on a leaf of 29 cm long x 13 cm wide; there was extensive feeding from much of one margin about half way to the midrib, and a long narrow flap was folded under to form the pupal shelter ( Figure 33 ). The shelter was lined with silk lightly sprinkled with white waxy powder, and the pupa was held with a simple silk girdle.

The prepupa head measured 2.9 x 3.2mm wide x high; light brown; a black spot 0.9 x 1.2mm centrally on the upper part of the face, extending to overlap the top of the adfrontals, but not on them; a similar smaller spot ventrolaterally covering the stemmata and extending dorsally in a pear shape; light dusting of white waxy powder on lower part of head including ventrolateral spot. Pronotum light brown. Body light green, dorsal line darker; spiracles light brown, conspicuous; all legs concolorous. There were ventral wax glands, but their distribution could not be recorded without disturbing the prepupa.

The pupa ( Figure 34 ) was 23mm long; elongate, with a blunt translucent frontal spike of 1.4mm, and the proboscis projecting beyond the cremaster; light bright green through a translucent cuticle; marked in blackdorsal line mostly a series of diffuse lines from A1–A8, but sharp in short sections on T1, anterior to a quadrate spot at rear of thorax, and heavy line on A9; row of 7 dorsolateral dots on A1–A7, and 8 lateral spots on T2, T3 and A2-A8; T1 spiracle convex, the central area, 0.8mm in diameter consists of densely packed light brown rods, and is surrounded by a narrow white margin, widest anteriorly and narrowest posteriorly. The cuticle of the emerged pupa was transparent and fragile.

The head markings of the caterpillar and especially the form and markings of the pupa are unique in our experience, suggesting that Osmodes is not closely related to any other Afrotropical genera for which the early stages have been documented. This view is supported by the distinctive genitalia (T.B. Larsen pers. comm. 2015).

Figures

FIGURE 32. Pinned adult female of Osmodes? adon collected as prepupa on Sarcophrynium brachystachys, Forêt du Yapo, Côte d’Ivoire, 6 Jun 1989; adult 25 Jun; MJWC 89 / 214. Scale bar = 10 mm.

FIGURE 33. Diagram of the leaf and shelter of a prepupa of Osmodes adon on Sarcophrynium brachystachys, Forêt du Yapo, Côte d’Ivoire, 6 Jun 1989; MJWC 89 / 214. The leaf measured 29 x 13 cm, and the lightly shaded area represents the flap folded under.

FIGURE 34. Pupa of Osmodes adon, dorsolateral view; collected as prepupa on Sarcophrynium brachystachys, Forêt du Yapo, Côte d’Ivoire, 6 Jun 1989; adult 25 Jun; 22 mm; MJWC 89 / 214. 1, photographed 14 Jun; 2, photographed 24 Jun.