]_gg Philippine Journal of Science «i» 



Genus TRIOZA Foerster 



Trioza is a very large genus of which many of the species are 

 difficult to distinguish. It appears to be a group in which very 

 active evolution of new species is in progress, especially in the 

 North Temperate Zone. In the Tropics and the South Tempe- 

 rate Zone it is much less numerously represented, most of the 

 triozine species there being in other genera, chiefly Megatrioza 

 with its armed hind tibise. With Cecidotrioza Kieffer I am un- 

 familiar. Whether or not it is truly distinct from Trioza or 

 Megatrioza is not yet clear. 



Key to the species. 



a\ Hind wings normally developed, at least half as long as forewings. 

 b 1 . Forewings more or less colored, not wholly clear. 



c 1 . Dorsum and vertex hairy; forewings thickened and darkened on 

 basal third, remainder glassy. 

 d\ Forewings nearly three times as long as broad; media and 

 cubitus each forking beyond its midpoint. (Japan.) 



T. (Trichochermes) bicolor Kuwayama ('10: 54). 

 d\ Forewings two and one-half times as long as broad; media and 

 cubitus each forking at or near its midpoint, making the mar- 

 ginal cells relatively longer. (Philippines.) 



X. divisa Crawford ('17: 172). 

 c 1 . Dorsum and vertex not hairy. 



d 1 . Forewings somewhat coriaceous, dull opaline in color, about 

 two and one-half times as long as broad. (Tasmania.) 



T. tasmaniensis Froggatt ('03: 329). 

 d'. Forewings semitransparent, somewhat browned, about four times 

 as long as broad. (Tasmania.) 



T. dobsoni Froggatt ('03: 331). 

 V. Forewings not colored, glass clear or sometimes very slightly yellowed 

 or smoky. 

 c l . Forewings broadly rounded at apex, not angular nor acutely pointed, 

 less than three times as long as broad. 

 d\ Genal cones distinctly shorter than vertex. 



e x . Forewings nearly three times as long as broad; antenna? long; 

 forming galls on Eucalyptus. 

 f. Legs short, stout; genal cones with long hairs. (Australia.) 



T. orbiculata Froggatt ('01: 274). 

 f*. Legs long and slender; genal cones less hairy. (Australia.) 



T. eucalypti Froggatt ('01: 277). 

 e~. Forewings not more than two and one-half times as long as 

 broad; antennae rather short. 

 f 1 . Body light green; genal cones very short; curling foliage of 



Olearus. (Tasmania.) T. oleariae Froggatt ('03: 332). 



f. Brown to almost black; genal cones one-half to two-thirds as 

 long as vertex; forming galls on Metrosideros. (Hawaii.) 

 T. ohiacola Crawford ('18: 442). 

 d\ Genal cones as long as vertex or sometimes longer. 



