The genus Poecilimon, with more than 150 species, is the largest genus of the family Phaneropteridae. According to DNA data (Ullrich et al. 2010) the most basal branch of the genus is formed by the P. hamatus group (Hamatopoecilimon n. subgen.). The coloration and a male calling song composed of series of short syllables, which follow each other at a relatively high frequency (9–26 Hz at 25°C), are important characteristics of this group. For all species of the subgenus, male calling songs, stridulatory movements (except for one species), and diagnostic genital morphology are described and figured. The females respond acoustically to the male song with a delay of about 30 ms. In four of six species the males have been observed to use two types of calling song, obviously connected to the female response behavior. The reasons for this behavior are discussed, as well as the phylogeny of the group, considering also its biogeography.