THE SENSE REACTIONS OF FLIES. 



143 



Some results giving percentages 

 below in Table I.. 



Potassium iodide 

 Potassium sulphate 

 Casein control 

 Sodium sulphate 

 Sodium iodate 

 Sodium phosphate 

 Honey -j- methylene blue 

 Honey + cochineal 

 Honey + thiosinamine 

 Ammonia 

 Ammonia alum 

 Ammonium carbonate 

 Ammonium tartrate . . 

 Sodium phosphate 

 Potash alum 



of the sexes coming to various baits are given 



Table I. 



d 



^/ 



9 



7 



. . 10 



2 



.. 17 



14 



. . 10 



4 



4 







5 



4 



. . 20 



14 



. . 14 



10 



3 



1 



. . 11 



8 



. . 14 



10 



. . 36 



8 



. . 21 



14 



5 



5 



2 



2 



Boric acid 



Control (honey + water) 

 Ammonia -j- honey -4- water 

 Ammonia -f- sand 

 Ammonium sulphocyanide . . 

 Ammonium sulphate 

 Sodium acid phosphate 

 Honey -4- water 

 Ammonia -4- honey 

 Casein mixture -f- thiosinamine 

 Casein mixture (control) 

 Ammonia + brown sugar 

 Ammonia + casein mixture . . 

 Ammonium nitrate 



<J 







4 



4 



2-5 



2-5 



25 



25 



10 



10 



3 



3 



2-5 



2-5 



2-5 



5 



3 



11 



13 



18 



1 



4 



4 



15 



57 



87 



21 



29 



3 



5 



The most suitable medium for use in the experimental tests was found to be the 

 casein mixture, since this was attractive to Musca and not disliked by the other 

 species ; the mixture consisted of equal parts of casein, sugar and banana, to 

 which a solution of the substance to be tested was added, or if insoluble, it was 

 stirred up in water and then mixed into the casein, etc. 



Some experiments were also made with various flowering plants and vegetables 

 on free flies, to see if any of them would be of practical use against flies, either to 

 attract them or to keep them off. For this purpose 46 different kinds of plants 

 were used, but none of them had any practical value as attractions or deterrents. 

 The flies, however, discriminated between them, showing preferences for some and 

 dislikes for others ; this was especially marked in the case of Aaron's Rod or Golden 

 Rod (Solidago virga-aurea), which attracted large numbers of blow-flies (Lucilia, 

 Calliphora and Phormia), although to the vast majority of the plants they appeared 

 to be indifferent. Tomato fruits, cut in half, were visited by considerable numbers 

 of Phormia ; and over-ripe apples and rotten carrots attracted many Lucilia, 

 Calliphora and Phormia. 



Alcoholic and water extracts, also, were made from some of these plants that 

 seemed to be the most attractive or disliked. These were tested as baits, as well 

 as being sprayed upon captive flies in balloon traps. But in neither case were 

 results of any practical value obtained. The following is a list of the plants from 

 which extracts were made : — Ragwort (Senecio jacobaea), flowers and leaves of sweet 

 gale (Myrica gale), lettuce (Lactuca), flowers and leaves of tansy (Tanacetum vulgare), 

 and tomato fruit (Solarium lycopersicum). 



Experiments were also carried out with various groups of organic and inorganic 

 compounds, to find out whether any of them would be suitable to use as baits, 

 poisons or deterrents. 



The substances to be tested were generally added to casein mixtures, or pieces 

 of blotting paper were soaked in them. In most cases they were exposed to free 

 flies, as well as being fed to those confined in glass cylinders or otherwise. They 



