INSTITUTE AND COLLEGE, PUSA, FOR 1912-13. 79 



An attempt was made to repeat the observations of 

 Hindle and Merriman on the smell-reactions of Ticks 

 (Argas and Hyalomma), but I was unable to obtain the 

 same results. The matter is one of considerable interest, 

 and I propose to return to it. 



III. — Agricultural Work. 



This was practically confined to the subject of fruit-flies 

 of the genus Dacus. 



A poison-spray method, which depends for its efficacy 

 on the habit of the peach-fly (D. Zonatus) of sucking tenta- 

 tively at any little drop of moisture on a leaf, was tried 

 with excellent results. The proportion of affected peaches 

 in the sprayed plots was approximately 2 per cent, over the 

 whole period of picking, in place of the usual 45 — 60 per 

 cent. The cost of the method is very small compared with 

 the value of the crop, and should this year's results be con- 

 firmed by another season's work, they will have a very con- 

 siderable commercial importance. 



In the course of experiments on the chemotactic reac- 

 tions of male fruit-flies I have found that these insects are 

 strongly attracted by certain compounds allied to Eugenol 

 (C 10 H 12 O 2 ). These compounds thus constitute a means of 

 detecting the presence of the flies in a given locality with 

 a degree of certainty quite unattainable by any ordinary 

 method of observation. 



Using this chemical test in the course of a tour in 

 March through Bihar, the United Provinces, the Punjab, 

 and the North- West Frontier Province, I found that the 

 North- Western limit of the distribution of peach-fly practi- 

 cally corresponded with the South-Eastern limit of success- 

 ful peach-growing. 



Mr. and Mrs. Howard have shown that under the 

 climatic conditions which obtain at Pusa it is possible to 

 grow first-rate peaches. That peaches are not largely or 

 profitably grown in the Southern and Eastern portions of 

 the Gangetic Plain and in various districts in Southern 



