228 ANIMAL COLOEATION. 



wasps' bodies, and a few Lepidoptera "too worn for identifica- 

 tion." Among- the eighteen species are fonr Diptera without 

 any protection such as is supposed to be enjoyed by Volucella 

 inanis ; and Klinckel d'Hercnlais met with V. pellucida, not 

 a wasp-like species, in wasps' nests. The two-winged flies 

 or Diptera are diurnal in their habits, and must deposit their 

 eggs during the day-time ; added to this difficulty, due to the 

 probability that the wasps would resent in a very conclusive 

 fashion the presence of any intruder, is the additional difficulty 

 that wasps especially feed upon Diptera. They are said to 

 visit ripe fruit mainly in quest of the flies which congregate 

 there. If wasps and bees have the same unintelligible liking 

 for keeping pets that another group of Hymenoptera the 

 ants have, the whole series of facts may prove to have a 

 very different meaning, but one which is not quite in accord 

 with the theory of mimicry on the part of the Volucella. 



Vision of Insects. 



The question of visual perception among animals is one upon 

 which different opinions have been held. 



When an accurate observer like Sir John Lubbock says,* 

 " We know, as yet, very little with reference to the actual 

 power of vision possessed by insects," it is surely premature 

 to build up theories which often demand a sense of vision in 

 invertebrated animals precisely similar to that possessed by 

 ourselves. Nevertheless, Sir John Lubbock himself is con- 

 vinced that bees distinguish between different colours. A drop 

 of honey was placed upon blue and orange slips of paper, and 

 though the position of the 'papers was alternately transposed, 

 the bee invariably selected the blue. 



* " The Senses of Animals,'' Int. Sci. Series. 



