The paper presents a description of larva, pupa, imago (male) and karyotype of Chironomus amissum from southeastern Brazil. It belongs to pseudothummi cytocomplex with 2n=8 and chromosome arm combinations: AE BF CD G. Several fixed homozygous inversions distinguished arm A of the new species from that of Chironomus columbiensis Wülker et al. 1989 and Chironomus anonymus Williston, 1896. One homozygous inversion of arm F differentiated it from C. anonymus. Species-specific characters were presented in the larva, pupa and imago.
Chironomus amissum sp. n.; morphology; karyology; Chironomidae; Diptera; Brazil
