Eagris decastigma purpura Evans 1937

Cock, Matthew J. W. & Congdon, T. Colin E., 2011, Observations on the biology of Afro-tropical Hesperiidae (Lepidoptera) principally from Kenya. Part 2. Pyrginae: Tagiadini 2893, Zootaxa 2893 (1), pp. 1-66 : 25-26

Eagris decastigma purpura Evans 1937 ( Figure 18 )

The nominate subspecies, decastigma Mabille 1891 , was described from Sierra Leone, although the NHM has specimens from Nigeria, Cameroon and Congo only. Evans (1937) described purpura from Uganda and it is also found in Kenya (Kakamega Forest). Larsen (2005) recognised that purpura was a valid species but did not formalise this change, although he will in his forthcoming work on African Hesperiidae , on the basis of the distinct male genitalia (T.B. Larsen pers. comm. 2010).

Evans (1937) characterised this subspecies as having no costal fold in the male, but it does have a vestigial costal fold. Like E. nottoana , this species shows strong sexual dimorphism. The male is dark brown above with a strong purple sheen, and a bright dark yellow under hind wing, whereas, the female is more similar to those of E. sabadius and E. nottoana , and in common with E. nottoana it has a white under hind wing. In Kenya this species is restricted to Kakamega Forest, and even there it is seldom seen. I have only seen adults on one occasion, when several of both sexes were found along a short stretch of road between the Rest House and Ikuywa Stream (19 Aug 1988). I have also found a pupa near the Rest House, as described below.

Adult behaviour

The few adults that I have seen were feeding at flowers, particularly those of Justicia flava . Food plants

Unknown. The pupa which I found was on Aframomum ? zambesiacum ( Zingiberaceae ), but clearly the caterpillar had strayed from its food plant to pupate, a habit of this genus already noted under E. sabadius and E. lucetia above.

Pupa

The pupa is formed in a shelter similar to that used by other members of the genus, and similarly it is supported by a Y shaped silk girdle. It is 19mm long, and similar in shape and colouring to that of E. sabadius ( Figure 18 ). Frontal projection 0.9mm; the ventral side is bluntly bifurcate at apex; the dorsal side has a pair of small protuberances at about half way. Proboscis sheath extends two segments beyond wing cases. A small hump each side of dorsum, just anterior to the posterior margin of the T2. Spiracle T1 raised circular, yellow-brown; other spiracles, pale brown, inconspicuous. Ground colour mottled pale brown. Dark markings around spiracle A4 (large) adjacent to the termen of the fore wing; posterior to spiracle A7 (small); two subdorsal spots each side, arranged transversely in posterior half of the dorsum of A4; similar, but much smaller spots in A7. A thin layer of white wax on parts of the abdomen: dorsal line A2–cremaster; dorsolaterally on A2–A3; subdorsally and patchily laterally on A4–A9; appendages of thorax, but not forewing spaces 1A and 1B. The head, thorax (but not appendages) and abdomen have short inconspicuous, erect hairs, those on the ventral surface pale, otherwise brown; on the dorsal surface of the thorax and abdomen, each hair arises from the centre of a small circular pit.

Based on this example, the pupa differs from that of the three Eagris spp. treated above in that it is slightly larger, the white wax is more extensive on the abdomen, and the frontal projection has dorsal protuberances well short of the apex, whereas the frontal projections of the other three species are more or less quadrifurcate at the apex.

Figures

FIGURE 18. Pupa of Eagris decastigma purpura collected on Aframomum?zambesiacum, 1 Jul 1990, Kakamega Forest, photographed 4 Jul, 19mm, female emerged 12 Jul, 90/66.