Development of Haemoproteus balmorali, H. dolniki, and H. tartakovskyi was followed in experimentally infected biting midges Culicoides impunctatus on the Curonian Spit in the Baltic Sea. Wild-caught flies were allowed to take blood meals on naturally infected spotted flycatchers Muscicapa striata, chaffinches Fringilla coelebs, or crossbills Loxia curvirostra harboring mature gametocytes of these parasites. The engorged biting midges were collected, held at 14-18 C, and dissected daily. Mature ookinetes of H. balmorali, H. dolniki, and H. tartakovskyi were numerous in the midgut content 36 hr postinfection (PI). Oocysts were first seen in the midgut wall 3 days PI. They were numerous in the midgut on the fourth day PI. Sporozoites were seen in salivary glands 5 days PI. The percentage of experimentally infected biting midges with sporozoites of H. balmorali was 36.1%: 8.8% with H. dolniki and 31.2% with H. tartakovskyi. Culicoides impunctatus is likely to be an important vector of Haemoproteus spp. in Europe. All investigated species of parasites can be distinguished on the basis of morphology or size (or both) of their vector stages. Morphological features of the ookinetes, oocysts, and sporozoites should be given more prominence in the description of new species of hemoproteids.