Vol. xxiii] 



ENTOMOLOGICAL NEWS 



149 



Wing Production in Aphids (Hemip.)* 



By J. D. Neiils, University of California, Berkeley, Cal. 



The results obtained by Doctor J. Loeb by the use of 

 chemical salts on micro-organisms, suggested to Professor 

 vV. T. Clarke that some of the polymorphism exhibited by 

 Aphids might be due to the action of such salts. Accord- 

 ingly he experimented with a series of salts*. 



The method of introducing the salts into the insect was 

 as follows : Cuttings of rose, bearing a single apterous vivi- 

 parous aphid (Nectarophora rosae) were planted in five 

 four-ounce tumblers containing washed and sterilized sand. The 

 sand was wetted with saturated solutions of magnesium 

 chloride, magnesium sulphate, potassium phosphate, sodium 

 hydrogen phosphate and pure water, respectively. Records 

 extending through a period of three weeks were kept with 

 the result of an apparent and very striking effect of mag- 

 nesium salts. Since this paper is not accessible to many, 

 the results obtained by Professor Clarke are given in de- 

 tail in the following table: 



As pointed out in a paper by Professor C. W. Wood- 

 worth on Winged Aphids f the wilting of plants results 

 in a slowing down of the birth rate, also in bringing about 



* Journal of Technology, Vol. i, Berkeley, California. 

 t Entomological News, March, 1908. 



