98 



Cincinnati Society of Natural History. 



Chambers on sugar maple (Psyche, III, Q6, 1880). The 

 cocoon is ocherous, much flattened, very regularly oval in out- 

 line, and has a very distinct broad projecting rim extending 

 entirely around it. 



Types in my collection. 



I have made some rather interesting observations on this 

 species in regard to the rate of increase in the length of the 

 mine. These observations were originally undertaken to cor- 



Mine of A', saccharella. 



rect statements made by Chambers as to the extreme short- 

 ness of the duration of the larval period in this group, and 

 while entirely refuting his statement that "usually the entire 

 larval life does not exceed thirty-six hours," they are also 

 interesting as a record of the rate of growth of the mine. 

 The observations on each consecutive day were made as far 

 as possible, approximately 34 hours apart. The letters a, a', 

 b, b', etc., are used to indicate approximately corresponding 

 ages of the larvae. 



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