Gametocytes of Leucocytozoon spp. with roundish parasite-host cell complexes from Great tit Parus major blood samples. Two morphotypes were found during microscopic examination: Leucocytozoon majoris (A, B) in the individual H10/20R (lPARUS4) and Leucocytozoon fringillinarum (C, D) in the individual H83/21R (lPARUS22). Microgametocytes (A, C). Macrogametocytes (B, D). Short simple black arrow: parasite nucleus. Black arrowhead: nucleus of infected host cell. Methanol-fixed and Giemsa-stained. Scale bar 10 μm.