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Transactions British Mycological Society. 



thallus. But on the same leaf there may occur perithecia which 

 have no visible stroma, but only a slight attaching weft of 

 hyphae at the base. Barren stromata of Torrubiella are most 

 annoyingly common. 



Fig. I. Perithecia of Torrubiella. i. T. rubra; 2. T. luteorostrata; 3. T. tenuis; 

 4. T. sublintea; 5. T. tomentosa; 6. T. tarda; 7. T. ochracea. All x 33. 



In the first stage of formation of the stroma in the scale- 

 insect species of Torrubiella, the hyphae are thin- walled, about 

 2/x diameter, with numerous very fine hyphae, O'5-i/x in dia- 

 meter, encrusted with globose, hyaline granules. These fuse 

 into a membranous sheet, here and there hyaline and amorphous, 

 which constitutes a basal disc which attaches the fungus to the 

 leaf. The hypothallus retains this structure, with the addition 



