No. 382.] THE WINGS OF INSECTS. 711 
insect ahead. The flexibility of this area of the wing is increased 
by those changes which result in the formation of the pectinate 
type of branching. 
The extreme of the pectinate type of branching exists in the 
neuropterous genus Polystcechotes, in which the area traversed 
by the parallel veins is very broad. 
