This study nearly doubles the number of recognized species and subspecies of Neotropical Dasymutilla ( from 76 to 139). We include descriptions of 45 new species ( 21 from the female only, 23 from the male only, and one from both sexes), descriptions of the previously unknown males of D. pulchra ( Smith 1855) and D. scaber ( Fox 1894), and six new synonymies. New species are: D. argentea, D. atrata, D. baleygi, D. batui, D. bellatrix, D. bimaculata, D. boharti, D. brazilia, D. buenavista, D. campogrande, D. chalcocephala, D. chamela, D. chilcotti, D. chionothrix, D. cirrhomeris, D. citromaculosa, D. concordia, D. fimbriata, D. griswoldi, D. guanacaste, D. impressa, D. ionothorax, D. leve, D. loreto, D. mazatlanorum, D. mirabilis, D. mirapenis, D. modgudi, D. monstrosa, D. naranjo, D. niphopilis, D. nocticaro, D. parkerorum, D. rufipilis, D. sinaloa, D. sleipniri, D. spilota, D. spiniscapula, D. tomasi, D. truxali, D. twegeni, D. veracruz, D. wasbaueri, D. whartoni, and D. zoster. New synonymies are: D. fulgida Mickel 1928 and D. pallida Mickel 1937 under D. erythrina ( Say 1836); D. atrifulva Mickel 1928 under D. nogalensis Mickel 1928; D. gaumeri Mickel 1937 under D. ocyrae ( Cameron 1895); D. cobira ( Cameron 1895) under D. proclea ( Cameron 1895); D. ariadne ( Blake 1871) and D. solola ( Blake 1871) under D. toluca ( Blake 1871); and D. bosquensis Rohwer 1912, D. columbiana Mickel 1928, D. errans ( Blake 1871), D. sappho ( Fox 1899) and D. texensis Rohwer 1912 under D. vesta ( Cresson 1865). We also provide the first taxonomic key for the species of Neotropical Dasymutilla.