65 



LII. H. M. Morris. " Note on the Wheat Bulb Fly. 

 (Leptohylemyia coarctata)." Bulletin of Entomological 

 Research, 1925. Vol. XV., pp. 359-360. 



The method of control of this pest is based on the assumption 

 that the eggs are laid in the bare or partially bare soil away irom 

 the wheat. A recent examination of the soil fauna of the mangold 

 plots of Barn field at Rothamsted has resulted in the discovery 

 of a number of eggs of this insect. This observation affords 

 confirmation of the recent work of Gemmill who first recorded 

 the finding of eggs in field soil in Scotland. 



LIII. F. Tattersfield and H. M. Morris. " An 



Apparatus for Testing the Toxic Values of Contact 



Insecticides under Controlled Conditions." Bulletin 



of Entomological Research, 1924. Vol XIV., 

 pp. 223-233. 



This apparatus for determining the relative toxicities of con- 

 tact insecticides is so arranged that successive batches of insects 

 are sprayed under conditions as similar as possible, so that on 

 using various substances at different concentrations, the results 

 are directly comparable. It consists of a glass jar containing in 

 its lid an atomiser, through which is projected by means of com- 

 pressed air at known pressure a constant quantity of fine spray 

 upon insects placed in a dish inside the jar. Examples are given 

 of results obtained when different concentrations of nicotine are 

 sprayed upon apterous agamic females of A. rumicis. 



Two notes from the Statistical Department at Rothamsted 

 are included, one analysing the accuracy with which the instru- 

 ment sprays, and the other giving reasons for regarding the 

 concentrations which kill 50 per cent, of the insects sprayed as 

 the most suitable for the direct comparison of the toxicity of 

 insecticides. 



LIV. F. Tattersfield, C. T. Gimingham and H. M. 

 Morris. " Studies on Contact Insecticides." Part 

 1. Introduction and Methods. Part 2. A Quantitative 

 Examination of the Toxicity of Tephrosia Vogelii, 

 Hook, to Aphis Rumicis, L. (The Bean Aphis). 

 Annals of Applied Biology, 1925. Vol. XII., pp. 

 61-76. 



This paper deals in detail with the insecticidal properties of 

 Tephrosia Vogelii, Hook., which, with other species of this genus, 

 occurs abundantly in many parts of the world. The aqueous and 

 alcoholic extracts of its leaves and seeds are shown to be highly 

 toxic to Aphis rumicis, L., the toxicity of the alcohol extract 

 being of the same order as that of nicotine. Extracts of the 

 stems have not proved so poisonous. 



The plants of the genus Tephrosia seem to offer possibilities 

 for practical use as insecticides. 



