170 P. E. S. WHALLEY 



Opula lineata Whalley 

 Opula lineata Whalley, 1967 : 41, figs 13, 53, 76. 

 Distribution. Madagascar. Map 63. 



GNATHODES gen. n. 



Type-species, Gnathodes Helvetia sp. n. 



This genus is characterized by the enormous development of the gnathus and the 

 presence of a lateral process on the valve of the male. Various modifications, 

 reductions or loss of the gnathus have taken place in many genera of the Thyrididae 

 but the only other species where a similar enlargement and sclerotization of the 

 gnathus has taken place is in the Magnified species-group of the genus Dysodia 

 (Whalley, 1968). The female of Gnathodes fiscinella is unknown. The presence of 

 the anal plate over the anal papillae is unusual and it will be interesting to see 

 whether the unknown female of G. fiscinella has also developed this. Externally the 

 species of Gnathodes are similar to some of the species of Opula but the genitalia 

 are quite distinct. It is possible that, when the Oriental fauna is studied, more 

 species of this genus may be found. At present the relationship of Gnathodes with 

 other African genera is not clear. This genus is only known from Africa south of 

 Sahara. 



Generic description. Labial palps three-segmented. Proboscis present. Fore tibia 

 with epiphysis. Tarsi without spines. Hind tibia with two pairs of spurs. Underside of fore 

 wing with black and silver iridescent scales. Male genitalia with enormously developed and 

 sclerotized gnathus. Valves with strong lateral projection. Female with sclerotized plate 

 over anal papillae. 



Biology. No information. 



Key to the African Species of GNA THODES 



1 Black species. Fore wing with radial veins from cell. Gnathus with a pair of posterior 



pointing processes (PI. 46, fig. 260) ...... Helvetia (p. 170) 



- Otherwise coloured. Fore wing with R 3 +R 4 Gnathus with three, posterior 



pointing processes ........ fiscinella (p. 171) 



Gnathodes helvella sp. n. 



(PL 22, fig. 115; PI. 46, fig. 260; PI. 64, figs 407, 408) 



o\ Wing, 9-5-10 mm. Vertex white, frons flattened between eyes. Antennae minutely 

 ciliate. Labial palps upturned, just reaching vertex, third segment 1/2 length of second. 

 Thorax yellowish brown. Hind tibia with outer spur of distal pair 2/3 length of inner spur. 

 Fore wing, pattern as in PI. 22, fig. 115, yellowish brown with reddish brown markings. Median 

 area reddish brown, with reddish brown posterior part to subterminal fascia. Fringe dark. 

 Underside, black and silver iridescent scales in cell in fore wing and along anterior veins. Large 

 antemedial black patch, not reaching costal margin and black posterior subterminal band 

 running forward as far as \A . Black postmedial patch in centre of wing. Radial veins from 

 cell. Hind wing, colour as fore wing, thin reddish median fascia. Fringe dark. Underside 

 paler, no black and silver scales. 



