TCD MS 10515 folio 88 verso
But their most wonderful sense is that which guides them, which impells. The mass in the uniform direction. The long migration flights of the adult locust show how strong is this sense in the fully developed swarm. But it exists in each single locust. Scattered individuals are controlled by a directive influence as unerring as when they move in summers swarms. Locusts singly or in small groups make a direct course across the Red Sea of the Persian Gulf and in the desert I noticed that the adult locusts which were continually rising singly into the air disturbed by our advancing column, swept off to the west over our left flank and always in the same direction. And this sense, whatever it be, is as strong in the hopping insect as in the adult.