A process for protecting keratinous material with the aid of substantially novel pyridyloxytrifluoromethanesulfonanilides from pests that feed on keratin, said pyridyloxytrifluoromethanesulfonanilides having the formula ##STR1## wherein R.sub.1 and R.sub.2, each independently of the other, are halogen, haloalkyl, alkyl, nitro, cyano, alkoxy or haloalkoxy or alkoxycarbonyl, andn and m, each independently of the other, are 0 or a value from 1 to 3, with the proviso that if n or m>1, the substituents R.sub.1 and R.sub.2 may be identical or different, and that at least one substituent selected from the group consisting of halogen, haloalkyl and haloalkoxy is present in the molecule.The preparation of these compounds and the use thereof as active ingredients of compositions providing a mothproof and beetle-resistant finish are also described herein.