"resident of the former Landgraviate of Hessen-Kassel," western Germany; its soldiers being hired out by the ruler to fight for other countries, especially the British during the American Revolution, the name Hessians (unjustly) became synonymous with "mercenaries." Hessian fly (Cecidomyia destructor) was a destructive parasite the ravaged U.S. crops late 18c., so named 1787 in erroneous belief that it was carried into America by the Hessians.