Chemical investigation of the volatile oil of Pycnanthemum pilosum nutt††Abstracted from portions of a thesis submitted to the Graduate Faculty of the University of Nebraska by E. H. Djao in partial fulfillment of the requirements for the degree of Master of Science. Special acknowledgment is given to the Sioux Honey Association, under whose fellowship grant this work was completed, and to Frank Pellett, for his assistance in supplying plant material, and for initiating our interest in the subject of this investigation.