THYRIDIDAE OF AFRICA AND ITS ISLANDS 177 



Generic description. Proboscis present. Antennae bipectinate or ciliate, not simple. 

 Eyes without interfacetal hairs. Labial palps 2-segmented. Fore tibia with epiphysis. 

 Hind tibia with one pair of spurs. Tarsi without spines. Uncus simple, valve simple, without 

 process. Bursa without signum. 



Biology. C. pexa has been bred from galls on twigs of species of Terminalia. 

 C. pexa pexa has been bred from Terminalia sericea and C. pexa guttulata produces 

 galls on Terminalia avicennoides (Ufaruna, 1968). The host plants of the other 

 species is not known. 



Key to the African Species of CECIDOTHYRIS 



1 Antennae shortly ciliate ....... longicorpa (p. 184) 



- Antennae pectinate ........... 2 



2 (1) Large oval or round, white maculations with two prominent round or oval ones 



in median area ........... 3 



- Not so patterned, maculations, when present, small ..... 4 



3 (2) Reddish brown species, maculations tending to be oval. Tarsal claws bifid 



(PI. 68, fig. 446) parobifera (p. 181) 



- Brown species, maculations tending to be round. Tarsal claws simple 



orbiferalis (p. 181) 



4 (2) Small maculations all over wing (PI. 2, R, S), particularly in terminal and sub- 



terminal areas. Male with median process to gnathus . tyrannica (p. 182) 



- Maculations, if present, restricted to median and basal areas. No median process 



on gnathus ............ 5 



5 (4) Hind wing with narrow median fascia (PI. 23, fig. 122) . chrysotherma (p. 180) 



- Hind wing with broad median fascia, usually with small maculations in it 



(PI. 2, N, O) pexa (p. 177) 



Cecidothyris pexa (Hampson) 

 Rhodoneura pexa Hampson, 1906 : 117. 



This species is widespread over Africa south of Sahara. It produces galls on 

 species of Terminalia. These galls are very similar to those produced on Muhlen- 

 beckia australis by the New Zealand Thyridid, Morova subfasciata Walker (Arnold, 

 1966). In west, east and central Africa specimens of this species are dark brown 

 with heavy markings on the fore and hind wings. From Rhodesia to South Africa 

 the specimens are much paler in colour on the wings. There is some overlap in the 

 intensity of colouration of specimens from Rhodesia, some being darker than the 

 typical southern specimens. Examination of the scales on the fore wing shows that 

 the pale southern specimens tend to have longer and more slender scales than the 

 darker specimens, otherwise they are morphologically similar. There is a tendency 

 for light coloured males from the south to be smaller than the males from the rest of 

 Africa. A fair amount of individual variation exists within the light and dark 

 series. I regard the two series as subspecies of one widely distributed species. In 

 the genus Cecidothyris, although there is some variation in wing pattern within the 

 species, there is little intra-specific variation in the genitalia. Considerable variation 

 in wing size exists in both sexes but the females are generally larger than the males. 



