SIR J. LUBBOCK OK ANTS, BEES, AND WASPS. 371 



At 10 they were under the chlorate of copper. I shifted the 

 liquids. 

 10.15 ditto ditto ditto. 



12.30 ditto ditto ditto. 



12.45 ditto ditto ditta. 



Subsequently I used saffron instead of the chlorate of copper: — 

 At 11 they were under the saffron. I shifted the liquids. 

 11.15 ditto ditto ditto. 



11.25 ditto ditto ditto. 



11.35 ditto ditto ditto. 



I now took successively red, yellow, and green glass ; but in 

 every case the ants preferred the glass to the bisulphide. 

 Although, therefore, it would seem from the previous experiments 

 that the bisulphide darkened the nests to the ants more than violet 

 glass, it would appear to do so less than red, green, or yellow. 



I now made some experiments in order, if possible, to deter- 

 mine whether the reason why the ants avoided the violet glass was 

 because they disliked the colour violet, or whether it was because 

 the violet glass transmitted more of the ultra-violet rays. 



For this purpose I placed a layer of the bisulphide of carbon 

 over a piece of violet glass. By this arrangement I got the violet 

 without the ultra-violet rays ; and I then contrasted this combi- 

 nation with other coloured media. 



First, I took a solution of bichromate of potash (bright 

 orange), and placed it on a part of the nest side by side with the 

 violet glass and bisulphide of carbon. I should add that the 

 bichromate of potash also cuts off the ultra-violet rays. In all 

 the following observations I changed the position after each 

 observation. 

 At 1.30 p.m. the ants were under the bichromate. 



3 „ „ half under the bichromate and half 



under the violet glass and bisulphide. 



8 a.m. „ „ under the bichromate. 



8.30 „ „ under the violet glass and bisulphide. 



9 „ „ half under each. 



9.30 „ „ some under each, but most under the 



violet glass and bisulphide. 

 9.45 „ „ half under each. 



10 „ j> J> JJ 



In this case, therefore, though without the layer of bisulphide 

 the violet glass would always have been avoided, the result of 



