The larva and pupa of Culex
) ocossa Dyar & Knab are redescribed and those of Culex (Melanoconion) delpontei
Duret and Culex (Melanoconion) pereyrai
Duret are described from specimens collected in the states of São Paulo and Paraná, Brazil. The pupa of Cx. ocossa
differs from those of the other two species in having seta 5-IV-VI dark with strongly aciculated branches, and caudolateral angle of segment VIII produced into sharp point, and seta 1-P present; Cx. delpontei
can be distinguished from Cx. pereyrai
in possessing paddle lightly tanned, trumpet flared, and wing and leg cases lightly tanned, without pattern of dark spots; Cx. pereyrai
can be recognized by having wing case with pattern of dark, discontinuously pigmented, longitudinal lines, and trumpet cylindrical, not flared. The larvae of the three species share the presence of seta 2-C placed medially to seta 1-C.