June, '10] YOTIIERS : HYDROCYANIC GAS EFFECTS 319 



rest of us were compelled to postpone the work for a few minutes. 

 Our hearts thumped against our breast bones and one fellow vomited. 

 All of us were well on the following morning and felt as if nothing 

 had happened. On this night we did not realize the importance of 

 hurrying away from the tent as soon as it was raised with the poles. 

 It was unnecessary this time and could have been easily avoided. 



The only object of writing these experiences is to enable one to tell 

 when they are getting too much gas. If the heart beats very rapidly 

 it is time to get away for a while. A small amount of gas is not un- 

 comfortable to a fumigator and is seldom noticed at all. Sometimes 

 a prolonged exposure to a small amount of gas- causes coughing which 

 is nothing serious. If tents are left on the trees the proper length of 

 time and those men nearest the tent when first raised take proper 

 precautions, there is little or no danger and the poisonous fumes do 

 not interfere with the process at all. 



Scientific Notes 



Simulium and Pellagra. — We learn from the Loudon Times through a 

 recent issue of Science, that Dr. Sambon has proved that maize is not the 

 cause of Pellagra, the blood thirsty Simulium reptaus being responsible 

 for the dissemination of this infection. It is hardly necessary to remind 

 our readers that only a few years ago the important part played by 

 Diptera in the dissemination of human diseases was practically unknown. 

 The order must now be considered as one of the most important from 

 an economic standpoint, especially because of the part flies play in the 

 spread of disease. 



Oyster Shell Scale {Lepidosaplies ulml Linn.). — The paper on this insect 

 by Mr. Cooley, was very interesting. We have entirely cleaned badly infested 

 trees by spraying with a lime-sulfur wash and then failed on adjacent trees, 

 no matter how carefully the application was made, though we usually suc- 

 ceeded in reducing the numbers of the pest. The experience of the last six 

 years convinces us that the late spring application is by far the more effective. 

 One season we treated about half an acre of large, imported lilacs which were 

 nearly dead because of injury by the oyster shell scale. A very thorough 

 application was given when the lilacs were in bloom, and an examination in 

 the fall showed that 90% of the shrubs were free, the remainder having a few 

 scales on one or two shoots only. An application of kerosene emulsion to 67 

 infested poplar trees resulted in practically cleaning the trees, as shown by 

 an examination the following winter. c. R. Neillie, Cleveland, Ohio. 



Larch Sawfly, a Correction. — I find that in the short paragraph of my paper 

 on the Larch Sawfly (page 149) that the stenographic report is not quite what 

 I said and is likely to mislead. I did not say that no males were present, but 

 that larvse were reared from females, no males being present ; and that, in a 

 total of several thousand specimens .3 per cent, were males and the rest 

 females. C. Gordon Hewitt. 



