188 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



brown as if blighted, while the leaves became discolored about the 

 wounded areas and curled. Microscopic mounts indicated that 

 tritici was more abundant on the trees than tabaci. For the identifica- 

 tion of the species, I am indebted to Dr. W. E. Hinds of the Alabama 

 Polytechnic Institute. 



President F. L. Washburn: Any discussion on this paper? 



Glenn W. Herrick: I should like to ask Mr. Parrott whether he 

 used the Black Leaf 40 or simple Black Leaf? 



P. J. Parrott: We used both preparations and we used thenx 

 alone, with soap and with kerosene emuslion. 



Glenn W. Herrick: At the usual strengths? 



P. J. Parrott: The mixtures were somewhat stronger than recom- 

 mended by Foster and Jones, because we had not received their pub- 

 lication at that time. Black Leaf extract was applied at the rate of 

 a gallon to sixty-five gallons of water and with five pounds of soap 

 while the Black Leaf 40 was used at the rate of 34 of a pint to a hundred 

 gallons of water with the same amount of soap. Nearly all the fruit, 

 growers have power spraying outfits, and there is no reason why most 

 of them cannot spray their orchards in a day, so that there certainly 

 will not be the difficulty in thoroughly spraying the trees as obtains 

 in California because of their extensive plantings. 



E. D. Sanderson: I would like to inquire how the insects hibernate. 



P. J. Parrott: I think that some of the members of the staff of 

 the Bureau of Entomology are much better prepared to answer that 

 question, but in New York the adult thrips are now in the ground. 

 We obtained the first specimen November 29th. 



President F. L. Washburn: Any other remarks on this paper? 

 The next paper on our programme is by Mr. Hunter of Texas. "Some 

 Experiments to determine the Effects of Roentgen Rays on Lisects." 



RESULTS OF EXPERIMENTS TO DETERMINE THE EFFECT 

 OF ROENTGEN RAYS UPON INSECTS 



By W. D. Hunter, Bureau of Entomology 



The whole science of radiology is of such recent development that 

 it is not surprising that but very few experiments have been performed 

 upon insects. In fact, a somewhat careful search through the liter- 

 ature has revealed but two accounts of experiments that have been 

 performed. One of these experiments was performed by Forel and 

 Dufour. It was with the European ant, Formica sanguinea. The 

 primary object of the experiment w^as to test the susceptibility of 



