REPORT ON THE DISEASES OF SILKWORMS IN INDIA 



15 



point in the life-history at which to start our description, as it[is 

 \yj means of the spore that infection is spread in the ordinary way. 



Text-figure A. Diagram of the life-history of Nosema bombycis. Modified somewhat from. 

 Stempell and Minchin. 



(1) Ripe spore with girdle of living substance with nuclei, two vacuoles and polar capsule 

 (2) Polar filament extruded.; planont about to leave spore-case. (3) Planont with empty 

 spore-case and polar filament immediately after leaving spore-case. (4) Planont with one 

 nucleus. (5) Fusion of two planonts or division. (6) Planont about to enter gut-wall cell. 

 (7) Meront in gut-wall cell. (8) — (11) Division of meront into two within gut-wall cell. 

 (12) — (14) Further divisions of meront. (IS) Meront ready to form spore. (16) First stage 

 in spore formation — one main and three subsidiary nuclei and one vacuole formed. (17) Further 

 stage in spore formation — thick spore-case secreted, two vacuoles and polar capsule. 



