The Association of Economic Biologists 



President 



Prof. E. B. POULTON, M.A., D.Sc, LL.D, F.R.S. 



Vice- Presidents 



Prof. V. H. BLACKMAN, Sc.D., F.R.S. 

 G. A. K. MARSHALL, C.M.G., D.Sc. 



Hon. Treasurer Hon. Editors 



A. D. IMMS, D.Sc., W. B. BRIERLEY, D.Sc. 



Rothamsted Experimental Station, D. WARD CUTLER, M.A., 



Harpenden Rothamsted Experimental Station, 



Harpenden 



Hon. Secretary (Qeneral and Botanical) Hon. Secretary (Zoolo£:y) 



W. B. BRIERLEY, D.Sc, J. WATERSTON, M.A.. D.Sc, 



Rothamsted Experimental Station, Nat. Hist. Museum, 



Harpenden South Kensington, S.W. 7 



Council 



W. LAWRENCE BALLS, Sc.D. G. A. K. MARSHALL, C.M.G., D.Sc. 



W. F. BEWLEY, D.Sc. J. W. MUNRO, D.Sc. 



Prof. V. H. BLACKMAN, ScD., F.R.S. S. A. NEAVE, D.Sc 



F. T. BROOKS, M.A. Prof. J. PERCIVAL, M.A. 



A. B. BRUCE, M.A. Prof. J. H. PRIESTLEY, D.S.O., B.Sc 



E. J. BUTLER, D.Sc, CLE., M.B. Sir JOHN RUSSELL, F.R.S. 



CONTENTS OF Vol. IX, Nos. 3 & 4 



PAOB 



1. A Study of the Life-History of the Onion Fly (Hylemyia antiqua, Meigen). By 



Kenneth M. Smith, A.R.C.S. (With Plates X and XI) 177 



2. The Smut of Nachani or Ragi (Eleusine coracana Gaertn.). By G. S, Kulkarni. 



(With 2 Text-figures) 184 



3. On the Young Larvae of Lyctus brunneus Steph. By A. M. Altson. F.E.S. (With 



2 Text-figures) 187 



4. Effect of High Root Temperature and Excessive Insolation upon Growth. By 



Winifred E. Brenchley, D.Sc, assisted by Kharak Singh, M.A. (With 2 Text- 

 figures) 197 



5. Studies in Bacteriosis. VII. Comparison of the " Stripe Disease " with the " Grand 



Rapids Disease " of Tomato. By Sydney G. Paine and Margaret S. Lacey . 210 



6. The Infestation of Fungus Cultures by Mites. (Its Nature and Control together 



with some Remarks on the Toxic Properties of Pyridine.) By Sibyl T. Jewson, 



M.Sc. and F. Tattersfield, B.Sc, F.I.C. (With 4 Text-figures) .... 213 



7. On the Development of a Standardised Agar Medium for counting Soil Bacteria, 



with especial regard to the Repression of Spreading Colonies. By H. G. 

 Thornton. (With 13 Text-figures) 241 



8. Studies on the Apple Canker Fungus. II. Canker Infection of Apple Trees through 



Scab Wounds. By S. P. Wiltshire, B.A., B.Sc. (With Plate XII) ... 275 



9. The Insect and other Invertebrate Fauna of Arable Land at Rothamsted. By 



Hubert M. Morris, M.Sc, F.E.S. (With 7 Text-figures) 282 



10. On the Life-History of "Wireworms" of the Genus Agriotes, Esch., with some 



notes on that of Athous haemorrhoidaUs, F. Part III. By A. W. Rymer 

 Roberts, M.A. (With 1 Text-figure and Plates XIII, XIV) 306 



11. The Accuracy of the Plating Method of estimating the Density of Bacterial 



Populations, with particular reference to the use of Thornton's Agar Medium 

 with Soil Samples. By R. A. Fisher, M.A., H. G. Thornton, B.A., and W. A. 

 Mackenzie, B.Sc. (With 2 Text-figures) 325 



