348 A KEVISION OF THE SUBFAMILY LIBELLULIN^E. 



f. Last antenodal cross nervure. 



g. Postnodal cross nervures. 



c-h. Principal radius, or subcostal nervure. 



k. Upper basal cell. 



JcJc. Lower basal cell. 



I. Arculus. 



l-s. Upper sector of the arculus. 



l-t. Lower sector of the arculus. 



m-n. Subcostal radius. 



m-o. Nodal sector. 



m-p. Subnodal sector. 



q. Supratriangular nervures. 



r. Triangle. 



u. Posttriangular cells. 



v-w. Upper sector of the triangle. 



v-iviv. Lower sector of the triangle. 



x. Subtriangular space. 



y. Subbasal sectors. 



z. Membranule. 



