328 THE ZOOLOGIST. 



insects ?* From experiments made with Ants, Lord Avebury 

 considers as proved that these insects perceive the ultra-violet 

 rays. As he remarks : — *' As every ray of homogeneous light 

 which we can perceive at all appears to us as a distinct colour, it 

 becomes probable that these ultra-violet rays must make them- 

 selves apparent to the Ants as a distinct and separate colour (of 

 which we can form no idea), but as unlike the rest as red is from 

 yellow, or green from violet. The question also arises whether 

 white light to these insects would differ from our white light in 

 containing this additional colour. At any rate, as few of the 

 colours in nature are pure, but almost all arise from the com- 

 bination of rays of different wave-lengths, and as in such cases 

 the visible resultant would be composed not only of the rays 

 which we see, but of these and the ultra-violet, it would appear 

 that the colours of objects and the general aspect of nature must 

 present to them a very different appearance from what it does to 

 us."t The late Prof. Riley was of the same opinion : — " So far 

 as experiments have gone, they show that insects have a keen 

 colour sense, though here again their sensations of colour are 

 different from those produced upon us."+ It is said that certain 

 night-flying insects invariably visit white flowers, as we reasonably 

 believe, because of the easy detection of that colour in an obscure 

 light, and we may accept the night preference to such flowers as 

 an undoubted fact.§ But we cannot say that the hue which we 

 describe as white is the same as that apprehended by the insects. 

 Distinct it must undoubtedly be to secure the permanent selec- 

 tion of their visits, but we can say no more. Because an insect 



* " What we, therefore, distinguish as light and colour arises from a 

 subjective property of the retina, inasmuch as it only reacts on certain other 

 vibrations. We might therefore imagine the existence of eyes which could 

 not perceive the intermediate parts of the spectrum as ours can, but only the 

 rays situated at the invisible ends. To such eyes the world would have 

 quite a different aspect." Cf. Bernstein, ' The Five Senses of Man,' p. 104. 



f ' Ants, Bees, and Wasps,' p. 220. 



+ Pres. Addr. Biol. Soc. Washington. Cf. ' Nature,' vol. lii. p. 210.— An 

 article appeared on "Animal Vision" in the 'Spectator,' June 8th, 1895, 

 which was really a contribution to the study. The writer remarked : — 

 " There is little positive evidence that the larger quadrupeds, Oxen, Deer, the 

 Felidce, or Dogs, have much sense of colour." 



§ Prof. Plateau afl&rms that "the admiration of insects for flowers does 

 not exist." (Mem. Soc. Zool. de France, vol. xiii. 1900. Cf. summary of 

 same papers, Ent. Month. Mag. 1901, p. 211.) 



