Dermestes (Dermestes) patagoniensis sp. n. from Chile and Argentina and D. (D.) boliviensis sp. n. from Bolivia are described, illustrated and compared with all related Neotropical species. Dermestes (D.) rufofuscus Solier, 1849 and D. (D.) elongatissimus Pic, 1916 are redescribed and illustrated. Dermestes (D.) haemorrhoidalis Küster, 1852 is recorded from Uruguay and Zambia for the first time.