The hindwings have a firm costal area, and a more delicate anal area which folds fanwise, so that they are completely covered by the forewings when the insect rests.
They resemble the Orthoptera more nearly than do any other group of the Linnean Neuroptera, having the anal area of the hind-wings folding fanwise beneath the costal area and the whole hind-wing covered by the forewing when the insect is at rest, though the forewing is not firmer in texture than the hind-wing, as is the case in the Orthoptera.
By pushing out divisions fanwise to E., N.E.
The hind wings, on the contrary, are for the most part membranous and, when extended, of large size; each consists of two portions, the distal of which, in virtue of the arrangement and jointing of its nervures, is capable of being both doubled up and folded fanwise beneath the proximal, which is partly horny when the wing is tucked away under the front wing-case of the same side.
Armagnac is a region of hills ranging to a height of 1000 ft., watered by the river Gers and other rivers which descend fanwise from the plateau of Lannemezan.