February, '16] MOORE: FUMIGATING ANIMALS 71 



lice. In just a week after the disease was first observed fully 30 per 

 cent of the lice on the plants were dead from it. At this time most 

 of the dead lice were immature apterous, and only a few pupae and 

 some winged lice. By the end of another week the lice were almost 

 entirely destroyed by the fungus. 



In the outdoor cages on January 7, 1914, the lice were found to be 

 dying rapidly from the fungus. The previous week had been mild, 

 though the last week in December 1913 had been very cold. The dead 

 lice at this time were mostly apterous and only a few winged lice. 

 By the end of a week the fungus had killed practically every louse 

 in the outdoor cages. The average daily mean temperature during 

 January 7 to 14 was 51° F. The fungus was again found in the out- 

 door cages on February 10. This was just four days after the low 

 temperature of 17° F. The fungus was prevalent in the outdoor 

 cages next on March 10. Two weeks later most of the lice had died. 

 On March 30 the disease was widespread in the louse-infested fields. 



Extensive experiments, extending over a period of two years, were 

 conducted on the artificial control of the turnip louse. It was found 

 that spraying was effective when properly done with a good material. 

 The soap solutions gave very satisfactory results. For the reason 

 that the whale-oil soaps are not generally available in Texas, laundry 

 soap is recommended. The secret of efficient application is in the 

 use of an extension rod, a 60° elbow, and an ''angle" type nozzle. 



President Glenn W. Herrick: I- would like to ask Mr. Paddock 

 if the turnip louse has the same pubescence as the cabbage aphis. 



Mr. F. B. Paddock: The first distinguishing point between the two 

 species is that the turnip louse is bare and the cabbage louse is covered 

 with pubescence. 



President Glenn W. Herrick: We will now listen to a paper by 

 Mr. William Moore. 



FUMIGATION OF ANIMALS TO DESTROY THEIR EXTERNAL 



PARASITES 



By William Moore, Assistant Professor of Entomology, University of Minn. 



Introduction 



During the past summer, a number of experiments were undertaken 



at the Minnesota Experiment Station in a search for new insecticides. 



The first work was with a number of essential oils in the hope that 



some of these might prove valuable repellents to insects. It was 



