The Mesoamerican genus Cataractocoris described by (Usinger, 1941) includes the following three valid species. Cataractocoris shepardiSites, (Reynoso & Novelo, 2013); it is known from Mexico (Chiapas, Jalisco, Nayarit, Oaxaca, Veracruz) and Guatemala (Escuintla, Suchitepéquez). Caratactocoris macrocephalus (Montandon, 1897); is recorded for Mexico (Chiapas, Jalisco, Estado de México, Morelos, Veracruz), Guatemala (Baja Vera Paz, Chimaltenango, Suchitepéquez), and El Salvador (Sites et al., 2013). Regarding the two male specimens of C. macrocephalus collected in La Majadita, CL. 1257, El Salvador, December 21, 1969, J. T. Polhemus and deposited in the Snow Entomological Museum Collection, University of Kansas, Lawrence, U.S.A. (Sites, 2004); the locality of those specimens is not correctly specified. This site could correspond to the Depto. Santa Ana, Municipio de Metapán, Cantón San José Ingenio, Caserío La Majadita.
On the other hand, Cataractocoris marginiventris Usinger, 1941 is recorded for Mexico (Estado de México, Chiapas, Guerrero, Jalisco, Morelos, Michoacán, Oaxaca, Puebla, Veracruz) and Guatemala (Baja Verapaz) (Sites et al., 2013).
The material was identified using the information proposed by (Sites et al., 2013) and the genitalia was examined. These specimens are deposited in the Aquatic Entomology Collection of the Zoology Museum of the University of Costa Rica (MZUCR), San José, Costa Rica and are preserved on ethanol 70%.
Cataractocoris marginiventris Usinger
MATERIAL EXAMINED: EL SALVADOR: Depto. La Libertad, Municipio Colón, Touristic Center Los Chorros, 13º41'42.29" N; 89º19'09.92" W, 792 msnm, 8-IX-2015, Col. F. Herrera, 3♂, 2♀ (MZUCR).
The specimens of C. marginiventris were collected on a vertical wall, covered with moss, of a waterfall which is consistent with the observations made by (Usinger, 1941) for C. macrocephalus. This finding represents the first record for El Salvador, which rises to two species of the genus for the latter country. In addition, it expands significantly the distributional range of the species to the south.