ULTRASTRUCTURAL-STUDY OF NOSEMA-OMANIAE SP-N (MICROSPORA, NOSEMATIDAE) PARASITE OF OMANIA-COLEOPTRATA (HETEROPTERA, OMANIIDAE)

Nosema omaniae (Microsporida, Nosematidae) is being described from Omania coleoptrata (Heteroptera, Omaniidae). The microsporidium attacks the adipose and nervous tissues and the muscles. All developmental stages are in direct contact with host cells cytoplasm and their nuclei are diplokaryotic. The meronts are bounded by a thin electron-dense wall and their cytoplasm contains some free ribosomes. The sporonts possess a thick electron-dense envelope and a cytoplasm with abundant ribosomes. The sporoblasts transform directly into diplokaryotic spores. Live mature spores measure 4.4+/-2 x 2.3+/-0.3 mu m. Their wall is composed of an electron-dense exospore (45 nm thick), consisting of an inner electron-dense layer and an outer layer that is less dense, and of a clear endospore about 85 nm thick. The polar filament is isofilar with 12 to 13 coils in one rank. The polaroplast possesses an anterior lamellar part and a posterior vesicular part.