Subfamily Anophelinae. Chagasia is a small genus of only five species. Genus abbreviation – Ch.
The adults of Chagasia are similar to those of Anopheles, but the resting posture is like culicine mosquitoes with the head and abdomen at angles to the thorax, and the scutellum is tri-lobed with setae in three distinct groups. The wings have dark scales or a mixture of dark and pale scales, but there are no distinct spots as there are in most Anopheles. Larvae have uniquely shaped palmate setae (seta 1) on abdominal segments III-V, and the spiracular apparatus bears a long median process and a fringe-like row of setae on either side. See Anophelinae.
Chagasia has been considered an ancient group showing affinities with non-anophelines. Cladistic analyses of morphological data and DNA sequences of various ribosomal, mitochondrial and nuclear genes strongly support the monophyly of Chagasia and its placement in an ancestral relationship to all other anophelines. See review of Harbach (2007).
Chagasia larvae are usually found in shaded streams among the roots of trees and in grassy margins or dead leaves and other debris. They sometimes occur in clear rock-pools along shaded streams. Adults remain in vegetation near the larval habitats or enter nearby forest canopy. Females bite during the day and night, but seldom feed on humans.
Species of Chagasia are not known to transmit any pathogens of human diseases.
Four species of Chagasia are restricted to South America and one (Ch. bathana) extends from Ecuador, Colombia and Venezuela through Central America into southern Mexico.