439 



Synopsis of Genera, 



A^ Forewings not opaque ; vertex not prodnced into processes 

 in front. 



B^ Hind tibiae withont basal spurs. 



C.^ Forewing with three narrow black spots on hind mar- 

 gin, one in each marginal cell and a third between 

 them ; veins without prominent setae. 



D^. Genal cones present Tiioza Foerster 



D-. Genal cones wanting Kiiicayama Crawford 



C-. Forewing without marginal spots ; veins with promi- 

 nent setae Hevaheva Kirkaldy 



B-. Hind tibiae with basal spur and subapical spine. .-. 



Megatrioza Crawford 



A-. Forewings opaque or nearly so ; vertex produced in front 



into two protuberances above genae 



-. Cerotrioza Crawford 



Genus Trioza Foerster. 



This genus has representatives in practically all countries 

 where Psyllidae occur. There are five closely related endemic 

 species in this archipelago, so far as known all living on the 

 foliage of ohia lehua {Metrosideros spp.). It seems quite cer- 

 tain that all are derivatives of a common ancestor which estab- 

 lished itself here long ago, coming probably from some land 

 area in the south Pacific. Living species resembling these in 

 essential characters and certainly allied to them are known in 

 Polynesia, Australia and South America, but it is not possible 

 yet to make a more definite statement of the ancestry of these 

 species. 



The ancestral species has apparently divided by variation 

 in the following manner: Trioza iolani and ohiacoJa are prol)- 

 ably concurrent derivatives from the original species on the 



