216 
fore-wings down to the alar bridge in three cases. In two of 
them, Amphiscepa bivittata and Thionia simplex, the costal 
trachea is shown arising from the bridge; in the third case, 
Scolops, it arises from the subcosta. In all the genera that | 
have examined so far the trachea agrees with Scolops and arises 
from the subcosta. In these latter cases the question arises as 
to whether this trachea is homologous with the costa. Tillvard * 
has shown that the Dipteron, Comptosia sp., has a distinct costa 
arising from the alar trunk and a humeral arising from the 
subcosta. He has also shown good reasons for regarding the 
humeral and Sc’ as homologous. If Metcalf had not shown that 
in two cases this trachea arises from the alar trunk, I should 
not hesitate to consider the costa as absent and the humeral 
(or Sc’) as present in all the fulgorids. While I shall use the 
term costa for this vein, I leave its true homology an open ques- 
tion whose solution will influence our conception of the primi- 
tive type of venation of the group. 
By calling this vein the costa we are faced by the fact that, 
in a large proportion of the fulgorids, the costa vein and costa 
margin do not coincide, but the vein lies considerably within the 
membrane, leaving a precostal cell or costal area. This is a con- 
dition recognized in no other order of insects. In certain genera, 
such as Niphidium, Conocephalus, and some Blattidae, there 1s a 
trachea arising from the subcosta, which appears homologous to 
the vein under discussion, but Comstock refrains from calling it 
a costa. 
The second point is the supposed movement of Al to Cu. 
This has been discussed by ‘Tillyard,? and I consider that his 
contention, that Cu does have more than two branches, is more 
logical than the contrary. Metcalf* remarks that the Cu and 
first anal “are united for a short distance from the body trachea 
and cubitus is usually two-branched,” but he gives no evidence 
to show that a branch of A moves over to Cu, but accepts it 
from Comstock and Needham. 
The cubital system of the Homoptera, and also of the Corro- 
dentia, is identical with that found in neuropteroid insects such 

1 Tillyard, 1919, Pro. Linn. Soc., New South Wales, p. 548, fig. 50. 
Bits Coy 10a Se 
3 Metcalf, Ann. Ent. Soe. Amer., VI (3), pp. 341-351 (1913). 
