,, ^ PROCEEDINGS 



OF THE 



American Philosophical Society 



HELD AT PHILADELPHIA 



FOR PROMOTING USEFUL KNOWLEDGE 

 Vol. LVII. 1918. No. 4. 



CONTENTS 



PAGE 



A Study of Some Ant Larvae, with a Consideration of the Origin and 

 Meaning of the Social Habit among Insects. By William Mor- 

 ton Wheeler 293 



Development of Magnetic Susceptibility in Manganese Steel by Pro- 

 longed Heat Treatment. By Charles F. Brush 344 



Preliminary Notes on Some New Species of Agarics. By Geo. F. 



Atkinson 354 



PHILADELPHIA 



THE AMERICAN PHILOSOPHICAL SOCIETY 



104 South Fifth Street 



1918 



