SIB JOHN lUBBOOK ON ANTS, BEES, AND WASPS. 285 



Observation. [and green. 



1 Yellow. Green. Purple. Violet. The pupa were brought under the yellow 



2 Violet. Yellow. Green. Purple. „ ,, green. 



3 Purple. Violet. Yellow. Green. „ „ „ 



4 Green. Purple. Violet. Yellow „ „ „ 



5 Yellow. Green. Purple. Violet. „ „ yellow. 



6 Violet. Yellow. Green. Purple. „ „ 



The results, then, were the same as in the previous eases. 



In these experiments, then, the violet and purple affected the 

 ants much more strongly than the yellow and green. 



It is curious that the coloured glasses appear to act on the ants 

 (speaking roughly) as they would, or, I should rather say, inversely 

 as they would, ona photographic plate. It might even be alleged 

 that the avoidance of the violet glass by the ants was due to the 

 chemical rays which are transmitted. From the habits of these 

 insects such an explanation is very improbable. If, however, the 

 preference for the other coloured glasses to the violet was due to 

 the transmission and not to the absorption of rays — that is to say, 

 if the ants went under the green rather than the violet because 

 the green or red transmitted rays which were agreeable to the 

 ants, and which the violet glass, on the contrary, stopped — then, 

 if the violet was placed over the other colours, they would become as 

 distasteful to the ants as the violet itself. On the contrary, how- 

 ever, whether the violet glass was placed over the others or not, the 

 ants equally readily took shelter under them. Obviously, there- 

 fore, the ants avoid the violet glass because they dislike the rays 

 which it transmits. 



Mr. Busk suggested that as the red glass stops the chemical 

 rays more eifectually than the yellow or green, while the violet 

 is most transparent to them, and as the ants prefer the red 

 glass to the yellow or green, and these, again, to the violet, possibly 

 the explanation might be that the chemical rays were peculiarly 

 distasteful to them. To test this, therefore, I made some ex- 

 periments with fluorescent liquids which Mr. Hanbury was 

 kind enough to procure for me from Mr. Benger, of Manchester. 

 They were prepared by M. Caro, of Manheim. One was opake 

 grass-green by reflected light and orange by transmitted ; one 

 violet by transmitted light and red by reflected; and a third 

 green by transmitted and red by reflected light. I believe their 

 exact chemical composition is not known, but that, in all cases, 

 fluoresciue is the principal ingredient. They stop the chemical 

 rays, or rather turn them into visible rays. The action takes 



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