THE 



VARIATION OF ANIMALS 

 IN NATURE 



BY 

 G. C. ROBSON, M.A. 



Deputy Keeper of Zoology, British Museum (Natural History) 



AND 



O. W. RICHARDS, M.A., D.Sc. 



Lecturer in Entomology, 

 Imperial College of Science and Technology 



With 2 Coloured Plates and 30 Illustrations in the Text 



LONGMANS, GREEN AND CO. 



LONDON ♦ NEW YORK ♦ TORONTO 







