428 Agricultural Experiment Station, Ithaca, N. Y. 



buff color at iirst which afterward becomes orange. In old cnltiires, 

 long attenuated, the general color becomes buff or even pale orange. 

 A half-litre Ehrlmeyer-llask containing about 2 cm. in depth of 

 potato on the bottom, was inoculated with conidia of Isaria fari- 

 nosa. A very luxuriant, loose and white growth soon appeared, 

 many sporophores being produced from 2|^ to 4 cm. in length, 

 covered with a farinaceous coat of conidia on the distal half. The 

 Hask, which had been previously kept in the dark, was placed in the 

 light. In a short time a bright orange-color replaced the white to 

 a great extent. On returning the flask to the dark, the growth be- 

 came pale and a white, flocculent growth soon overspread the entire 

 culture On again bringing it to the light the orange-color 

 reappeared. 



Experiments. 



A number of white grubs, the larvse of Lachnosterna, were 

 dusted with conidia both from the original specimen and from 

 potato culture, and after four months, no trace of the fungus was 

 visible. Although most of the specimens died, they showed no 

 trace of the fungus. 



Fifteen specimens of Pieris rapae (larvae) were dusted with 

 conidia from a potato culture. After about twenty days the adult 

 insects emerged. 



Seven specimens of our common brown-and-black caterpillar, 

 Pyrrharetia Isabella^ were infected with Isaria farinosa by stick- 

 ing the conidia on the ventral and lateral surfaces with the white of 

 an e^g, by means of a brush. After twenty days, all but two 

 showed that they were attacked by the fungus. Of the live attacked 

 four were dead, curled up and covered more or less denseJy with a 

 thick cottony mass of mycelium most prominent on the ventral 

 side. One was yet alive although the ventral side bore patches of 

 the mycelial growth. One of the dead larvie was placed in a pot of 

 sterilized sphagnum moss and placed in a moist chamber. After a 

 little more than a month it had become completely covered with 

 long Isaria-sporophores like those found on the original specimen. 

 The remaining caterpillars and the two which subsequently con- 

 tracted the disease, did not produce sporophores. They were left 

 in the original cage which was constructed as follows : an ordinary 

 flower-pot was placed inside of a large one and the space of about 

 ,2 cm. between them was packed with moss. The inner jar was 



