EXPERIMENTS WITH ELECTRIC LIGHT. 203 
in and near the thalline band, and carried them into 
the yellow or red. 
Experiment 6.—Repeated the same experiment. 
Begun it at 11.15. Placed some pupz in the red; some 
in the yellow, and a few scattered over the second 
apectrum; there were none in the nearer one. 
They were all carried away from the red past the 
violet, and put down in the dark portion, or in the red 
and yellow, of the nearer spectrum. 
These experiments surprised me much at the time, 
as I had expected all the pupz to be carried into the space 
between the two spectra; but it afterwards occurred to 
me that the ultra-violet rays probably extended further 
than I had supposed, so that even the part which lay 
beyond the thalline band contained enough rays to 
appear light to the ants. Hence perhaps they selected 
the red and yellow as a lesser evil. 
Experiment 7.—I altered, therefore, the arrange- 
ment. Prof. Dewar- kindly prepared for me a con- 
densed pure spectrum (showing the metallic lines) with 
a Siemens’ machine, using glass lenses and a mirror to 
give a perpendicular incidence when thrown on the 
nest. I arranged the pupe again in the ultra-violet 
as far as the edge of the fluorescent light shown with 
thalline paper. The pupz were all again removed, and 
most of them placed just beyond the red, but none in 
the red or yellow. 
Experiment 8.—Arranged the light as before, and 
placed the pup# in the ultra-violet rays. In half an 
