AND COLLEGE, PUSA, FOR 1914-15. 75 



of them would certainly simplify preventive 

 and antiseptic measures. 



(2) Energetic relations of insects : their consumption 



and economy of chemical energy under varying 

 conditions. Mr. S. K. Sen is obtaining data 

 for this investigation during my absence, in the 

 form of food, oxygen, and water curves for the 

 whole life-history of various insects. I hope 

 subsequently to correlate this work with 

 enzyme-investigations of the type recently 

 carried out by Mr. Barnes at Lyallpur. Re- 

 sults of practical importance may or may not 

 be obtained. 



(3) The pure chemical substances responsible for the 



" chemotactic " reactions of the males of three 

 species of fruit-fly have now been definitely 

 and certainly ascertained. They are methyl - 

 eugenol and iso-eugenol. Similar reactions in 

 the case of a small Oscinid are produced by 

 Isovaleric aldehyde. Analogous but not pre- 

 cisely similar cases are under observation. 



The immediate practical value of this work is almost 

 negligible ; its ultimate value may be large, since it indicates 

 the practical possibility of entirely new methods of insect- 

 control. It is far and away the most important result yet 

 achieved by the section. 



IV. Miscellaneous. 



(a) Lice. The lice of sheep and goats were investigat- 

 ed. A lime-sulphur spray or wash, followed by a spray of 

 weak vinegar, was found to give excellent results. Internal 

 administrations are being experimented with. On human 

 lice the effect of extremely small quantities of mercury 

 compounds was found to be very marked, though the way in 

 which they act is obscure. 



(b) Bugs. An attempt was made to elucidate the 

 nature of the " biting-reflex " in the bed-bug. The enquiry 

 proved difficult, but there were indications that the ventral 



