NATURAL SCIENCES OF PHILADELPHIA. 283 



moths proved tliat the sexes had been distinctly indicated b}' the dif- 

 ference in the breadth of the antennteas observed in the chr3'^salides. 

 During my observations and experiments the following additional 

 facts came under my notice : Firstly, that males are the inva- 

 riable result when the larvae are fed upon diseased or innutritions 

 food ; secondly, that in the fall of the year, when the leaves have 

 become deprived of their usual amount of sap, males are generally 

 produced ; thirdly, that more males are produced late in the sea- 

 son than females ; fourthlj^, that the sexes in early life cannot be 

 distinguished, or in other words, that there w^ould appear to be no 

 such distinction as male and female, the change being brougjit 

 about late in life through the medium of nutrition. 



