MICROSPORIDIA, HEUCOSPORIDIA 325 



The minute spore is composed of a thin membrane of one 

 piece and of three uninucleate sporoplasms, around which is 

 coiled a long thick filament. Young trophozoites are found in 

 the host tissues or body cavity. They undergo schizogony , at 

 the end of which uninucleate sporonts become differentiated. 

 A sporont divides apparently twice and thus forms four small 

 cells which develop into a spore. The complete life-history is 

 still unknown. 



Genus Helicosporidium Keilin. Parasitic in insects. Schizo- 

 gony and sporogony. The spore with central sporoplasms and 

 a single thick coiled filament. One species. 



Helicosporidium parasiticum Keilin (Fig. 139). In the body 

 cavity, fat body, and nervous sytem of the larva of Dasyhelea 

 ohscura (Diptera), also in Mycetobia \pallipes (Diptera), and 

 Hericia hericia (Acarina), all of which inhabits wounds of elm 

 and horse-chestnut trees. The schizont is minute. The spore 

 measures 5 to 6 microns in diameter; extruded filament 60 to 65 

 microns long by 1 micron thick. 



References 



Keilin, D. 1921 On the life-history of Helicosporidium 



parasiticum. Parasit., Vol. 13. 

 Kudo, R. 1924 A biologic and taxonomic study of the 



Microsporidia. Illinois Biol. Monogr., Vol. 9. 



