APHIDID^E. 317 



antennae is very long, being considerably longer than all the other 

 joints put together, and beautifully ringed. The wings are moder- 

 ately long, and the cubital vein is but once forked, which is an 

 important point in generic classification. 



Tribe PEMPHIGIN.E. 



Closely allied to the preceding group are the Pemphiginae or gall- 

 forming aphides. The insects live sociably, but instead of rolling 

 leaves, form galls, growths which, from a structural point of view, 

 may be considered higher in the scale of organisation than rolled 

 leaves. The curious abnormal growths, caused by insects belonging 

 to this tribe, appearing on the leaf-stalks or midribs of leaves, often 

 displaying beautiful colours, have received a great deal of attention 

 from various workers. The galls themselves, differing from one 

 another in appearance and position, give rise to specific characteristic 

 distinctions, apart from the structural points of the respective insects 

 themselves. 



In comparing the characters of the two genera, it will be ascertained 

 that the rostrums are alike, and the antenna? similar, viz., six-jointed; 

 but the sixth joint in Pemphiginae is larger than in Schizoneurinae. 

 It is, however, in the wings that the most salient structural difference 

 may be recognised. The cubital vein in Schizoneurinae is forked 

 once, whereas in Pemphiginae it is not forked, but in both genera the 

 cubital vein is unattached to the cubitus. 



Genus Pemphigus. 



The following are the generic characters according to Buckton : 



" Rostrum as in Schizoneura. Antennas short, with six joints, 

 omitting the nail-like process. Third joint about equal to the three 

 following taken together. The third, fourth, and fifth joints com- 

 monly ringed ; the sixth joint longer than that of Schizoneura. 



" Cornicles wanting. 



"Wings with no furcated cubital vein, this vein, as in the last 

 genus, being unattached to the cubitus ; stigma large and trapezoidal ; 

 the two oblique veins usually start from the same point. The post- 

 costal nervure of the hind wing somewhat angular, from which angle 

 the two oblique veins spring. 



" Legs short, particularly in the apterous forms." 



