Peiratinae is a cosmopolitan subfamily within Reduviidae with more than 300 known species in 34 genera. There are also some taxa endemic to islands, but their taxonomic status and biology require further study. After examining type specimens of the peiratine species distributed in New Guinea, we found that some of them share many morphological characters, though they were previously assigned in different genera. The phylogenetic analysis based on cytochrome oxidase I, 16S ribosomal RNA and 18S ribosomal RNA genes involving 38 species in 25 genera also supports the result of the morphological study that these species should be involved in a separate genus. In the present study, the subgenus Ectomocoris (Sigicoris) Miller, 1958 is elevated to genus level, Sigicoris stat. nov. Three new combinations, S. brumalis comb. nov., S. gracilis comb. nov., S. sexguttatus comb. nov. and one new species, S. dominiqueae sp. nov. are described or redescribed. The lectotype of Brachysandalus sexguttatus is designated, and Pirates concinnus syn. nov. is treated as the junior synonym of S. sexguttatus comb. nov. A key is provided to separate the four species of this genus. The systematic relationships, diagnosis, distribution and habitat of Sigicoris stat. nov. are briefly discussed.