The Association of Economic Biologists 



President 



Professor NEWSTEAD, F.R.S. 



Vice-Presidents 



Professor CARPENTER, M.R.I.A. 

 Professor HICKSON, F.R.S. 

 R. STEWART MacDOUGALL, D.Sc. 

 A. E. SHIPLEY, D.Sc, F.R.S. 



Council 



Prof. B. T. P. BARKER A. D. IMMS, D.Sc. 



S. E. CHANDLER, D.Sc. Prof. J. H. PRIESTLEY 



F. J. CHITTENDEN A. G. L. ROGERS 



E. E. GREEN E. S. SALMON 



Prof. P. GROOM, D.Sc. 



Hon. Treasurer 



J. C. F. FRYER, Esq., 



Craven House, 



Northumberland Avenue 



Hon. Secretary 



Professor PERCY GROOM, 



Imperial College of Science and Technology, 

 South Kensington 



CONTENTS OF Vol. Ill, No. 4 



PAGE 



Accessory Wetting Substances with Special Reference to Paraflfin 



Emulsions, By A. H. Lees, M.A 141 



Empusa Muscae versus Musca domestica L. By H. T. GiJssow. 



(With Plate XXI.) . . . . . . " . . . .150 



A Blossom Wilt and Canker of Apple Trees. By H. Wormald, 



M.Sc. (Lond.), A.R.C.Sc. (With Plates XXII— XXIV.) . . 159 



