THYRIDIDAE OF AFRICA AND ITS ISLANDS 151 



eyes. Thorax reddish brown. Hind tibia with outer spur of distal pair slightly more than 1/2 

 length of inner spur. Fore wing, pattern as in PI. 18, fig. 92, reddish brown with darker brown 

 transverse fasciae. Costal margin and basal area brown, fringe brown. Underside paler. 

 Radial veins from cell. Hind wing, colour and pattern as fore wing. Sc +i? x and Rs approach 

 closely but do not join. 



Genitalia 0* (PI- 4 2 - n g- 2 35)- Uncus simple. Gnathus lightly sclerotized, median part 

 very lightly sclerotized and slightly spiny. Valve simple with pointed, sclerotized, median 

 basal process. Juxta with two membraneous lateral lobes and two sclerotized lobes. Area 

 round transtilla minutely spined. Aedeagus with vesica minutely spined. 



$. Unknown. 



Discussion. This species shows some similarities to Opula impietalis Walker 

 but differs in the shape of the gnathus and the straight, not incurved, lobes of the 

 juxta. Superficially it is similar to ankole and eagrapha but can be distinguished by 

 the genitalia. The exact relationship of this island species to the mainland species 

 is not clear, it is probably derived from N . eugrapha but a closer comparison will have 

 to await the discovery of a female. 



Distribution. Map 69. Fernando Po (West Africa). 



Material examined. 



HolotypecJ, Fernando Po: Moka, 29.1.1933 (Tarns), BM slide no. 9913, in BMNH. 



Paratype. Fernando Po: i <J, Moka, 28.i-3.ii. 1933 (Tarns). 



Nemea nivosa sp. n. 



(PI. 18, fig. 93; PL 42, figs 239, 240; PI. 64, figs 403, 404) 



$. Wing, 14-18-5 mm. Vertex light brown. Antennae moderately ciliate. Labial palps 

 with third segment equal in length to second, upturned, not reaching vertex. Patagia brown, 

 rest of thorax white. Hind tibia with outer spur of distal pair 1/2 length of inner; longest spur 

 of distal pair slightly less than 1/2 length of inner and less than 1/2 length of 1st hind tarsal 

 segment. Fore wing, pattern as in PI. 18, fig. 93, snowy white with thin brown reticulations. 

 Underside darker, dark basal area. R x and R b shortly stalked in a few specimens. Hind 

 wing, as fore wing but with slightly heavier patterning on upper side. Sc+R 1 and Rs free. 



Genitalia £ (PI. 42, figs 239, 240). Uncus simple, long. Gnathus with median process 

 greatly enlarged and spiny. Valves long, simple. Basal process a large plate, together with 

 large spiny pouch. Juxta two small lobes, spiny at apex. Aedeagus without cornuti. 



?. Wing, 16— 19-5 mm. Colour and pattern as male. Labial palps long 2 X diameter of eye, 

 third segment of labial palp equal in length to second segment. Antennal ciliations shorter 

 than male. 



Genitalia ? (PL 64, figs 403, 404). Anal papillae short. Ostium lightly sclerotized. Duct 

 long and minutely spined. Bursa covered in minute spines. 



Discussion. Externally this species is similar to eugrapha but is distinguished 

 by the white coloured wings and very distinct genitalia. The enormous develop- 

 ment of the gnathus with its spiny covering and the enlargement of the basal process 

 of the valve into a spiny pouch are peculiar to this species. Variation is mainly 

 in size and intensity of the pattern. Specimens from the Cameroon have larger 

 spines on the gnathus than those from the Congo, these larger spines are also found 

 in specimens from Rhodesia. There is a tendency for some of the Rhodesian 

 specimens to be darker and smaller than other specimens. This species is fairly 

 widespread over Africa and on material available it is probable that the Rhodesian 



