Pupa of Culicoides insignis Lutz, 1913, and larva and pupa of <i>Culicoides bambusicola</i> Lutz, 1913 are fully described. They are illustrated and photographed using binocular microscope, phase-contrast stereoscope at oil immersion and scanning electronic microscopy, from material collected in Corrientes and Misiones provinces, Argentina. Palatum, maxilla and hypopharynx of the fourth instar larva of <i>C. bambusicola</i> as well as the cephalothoracic sensilla and sensillar pattern of the fi rst and fourth abdominal segment of the pupa are described for both species. The immatures of <i>C. bambusicola</i> are compared with <i>Culicoides debilipalpis</i> Lutz, 1913. Pupa of <i>C. insignis</i> is compared with the following related congeners: <i>C. maruim</i> Lutz, 1913, C. charruus Spinelli & Martinez, 1992, and <i>C. annetae</i> Spinelli & Borkent, 2004.Facultad de Ciencias Naturales y MuseoCentro de Estudios Parasitológicos y de Vectores