17 
shows the appearance of a plate culture on two different days, 
on the right the growth four days after sowing, and on the left 
eight days after. 

‘32 





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Fig. 7. Isaria verans, showing h, germinating spores; 0, production of cylindrical 
spore. 7. the same, later; | and k, production of first conidia; m, heads of conidial; n, 
anastomosing threads. Original. 
On potato the growth spreads over the entire surface ina 
felted layer, afterward becoming densely covered with a fari- 
naceous, creamy-white layer composed of colorless conidia. 
The threads by interlacing and growing away from the potato 
often produce Isaria-sporophores. One tube produced ten, 
ranging from two to four mm. in height. They are usually 
clavate in form, sometimes being three mm. in diameter at the 
apex, tapering to one mm. at the base. Sometimes these Isaria- 
sporophores cling to the glass and become flattened; such often 
grow to the length ofeight mm. Inold cultures, wherever the 
mycelium touches the glass, it is seen to be of a bright buff 
color. 
When grown in small flasks, where the supply of food is lar- 
ger, the development goes on further. The potato is colored 
a distinct purple. After about twenty days the entire surface 
