OF WASHINGTON. 125 



iveness of the beneficial fungi. The common means of dis- 

 tributing the fungous enemies of the white fly is by forming 

 water decoctions from masses of leaves covered with the fungi, 

 or by pinning infested leaves at different points on the trees 

 to be inoculated. 



In connection with this paper Mr. Marlatt exhibited photo- 

 graphs illustrating the white fly conditions and methods of 

 extermination at Marysville, Cal., some views of San Fran- 

 cisco, and some showing the oil wells of Santa Barbara, where 

 the insecticide oils are secured, and one of Salton Sea, where 

 the fishes come to the railway bridges to feed. In connection 

 with his remarks on the white fly of Florida he exhibited speci- 

 mens of the beneficial fungi and also those fungi that are 

 parasitic on the former. 



In the discussion that followed, Doctor Howard remarked 

 that the stimulation of the citrus trees by the fumigation with 

 hydrocyanic acid gas might be caused because the plant was 

 injured and was trying to reproduce itself before its powers 

 failed. Mr. Burgess thought that the seemingly stimulated 

 plants might seem to be stimulated because the fumigation had 

 retarded their normal development. He stated that this was 

 his experience with other trees, 



Mr. Schwarz called attention to the fact that southern Cali- 

 fornia, strictly speaking, was that part south of the San Ber- 

 nardino Mountains, and should be so noted by entomologists, 

 because it has a fauna peculiar to itself. Doctor Hopkins re- 

 marked that while the dry conditions in California are un- 

 favorable for the white fly, it is not improbable that through 

 natural selections of surviving individuals of such conditions 

 the species may survive and become a dangerous pest. If it 

 should survive it is evident that the conditions would be un- 

 favorable for its control by the fungous disease. He said 

 that entomologists should learn how fungous diseases are 

 perpetuated and disseminated in nature, with a view of utiliz- 

 ing the facts obtained in controlling injurious insects. As an 

 example, he cited the larch sawfly fungus of Europe and 

 America, which seems to destroy immense numbers of this 



