The present paper consists of a morphological revision of gregarines belonging to the genus Stenophora Labbé, 1899, specially referred to S. juli (Frantzius, 1848) Labbé, 1899. Nuclear compounds were cytochemically characterized and on account of the positive reactions for RNA the corpuscle generally referred as "caryosome" was to be a "nucleole". The finelly divided DNA of the nucleoplasm caused a weak reaction. The structure of the nucleole depends on the technic used. These results must be compared with those obtained with the electronic microscope.