Aileron: the scale covering the base of primaries in some insects; see tegulae in Diptera = alula and squama, q.v.
"Explanation of Terms Used in Entomology" by John. B. Smith
The Abyssinian heads were paraded and said to be those of Eas Alula, Eas Mariam, and Saleh Shanga; but this was not true.
"Ten Years' Captivity in the Mahdi's Camp 1882-1892" by F. R. Wingate
Ras Alula beat a hurried retreat, leaving the camp in the hands of his enemies.
"Fire and Sword in the Sudan" by Rudolf C. Slatin
On the 25th of January 1887 Ras Alula attacked Saati, but was repulsed with loss.
"Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 1" by Various
She will lie here, a ghost of their delight,
Their lucent stems all ashen gray,
Their purples fallen into pulvil white,
Dull as the bluebird's alula.
"The Violet Pressed In A Copy Of Shakespeare" by Duncan Campbell Scott