Seven new species of Homeomastax are described, two from Panama and five from Costa Rica; a further new species from Colombia is noted, but not described owing to the lack of a male. The genus now contains 22 species. On the basis of the male genitalia the genus can be divided into 4 species groups, represented by the species surda, bouvieri, kressi and silvicola respectively; those species known only from the female (dentata, richteri, annulipes, and the new Colombian form) cannot yet be arranged in this scheme. Apart from male phallic characters, the species are externally recognizable only by the male and female subgenital plates and by morphometric ratios, especially E/F (elytron: femur). Of the three species redescribed by Rehn & Rehn (1934), the originally missing male of surda Burr and the female of veraguae Hebard are shown to have been correctly assigned by those authors. Their redescription of H. dentata Saussure, however, is invalid, as the type is a different taxon. The phallic complex of the genus is described in detail, and observations on copulation and the nature of the spermatophore are presented. We suggest that the hooked and tapered end of the spermatophore may be used as an intromittent organ by the copulating male.

The natural history and geographical distribution of the genus is reviewed; it occurs west and north of the Andean chains, though it extends up the major inter-Andean valleys of Northern Colombia, and ranges from Ecuador to Honduras. The four species groups are largely disjunct geographically. The bouvieri-group is South American, with an outlying species (brachyptera) in Central Panama; the surda-group is confined to the Pacific slope, the kressi-group to the Caribbean slope, and the silvicola-group is known only from the Caribbean slope and mountains of northern Costa Rica and southern Nicaragua.