[New species of Microsporidia - Thelohania assovi Sp. N. (Microsporidia, Nosematidae) from the larvae of black flies].

A new species of microsporidians, Thelohania assovi sp. n., was found in population of larvae of Odagmia sp. inhabiting mountain rivers of Tien-Shan and south-eastern Kazakhstan. The infection of larvae with this species varies from single individuals to 18-20% while pupae are infected only with single speciments. The species differes from all known members of this genus in a number of characters. Size of 50 measured spores varied from 4.4-7.0 X 2.5-3.8 in live specimens to 3.8-6.4 X 2.3-3.8 mem in fixed ones. The parasite causes patho--morphological changes in injured tissues.