OBSEKVATIONS ON WOOD-LICE AND CENTIPEDES 47 



opportunities for the study of colour variations in common with 

 other groups, and it is only a long series of careful and systematic 

 notes as to various habitats and the characteristics of the individuals 

 which dwell in them that will enable light to be thrown upon the 

 matter. It is fairly easy to keep wood-lice in captivity, as all that 

 is necessary besides supplying them with food is to prevent the 

 atmosphere from becoming so dry that they cannot breathe. The 



FIGURE 176. A Centipede. 



gill-like breathing organs of wood-lice can only act in moist con- 

 ditions. Some simple but useful experiments would show whether 

 light or its absence affects in any way the colour of these creatures. 

 It is said that the handsome pink wood-louse has not its brilliant 

 colour when it lives in the dark. 



The females of some species are said to have eggs or young ones 

 in their brood pouch at most times of the year, and it would be 

 worth while to make careful records in order to discover whether 

 other kinds have not more restricted breeding seasons.* 



One British wood-louse is an inhabitant of ants' nests, and those 



* Messrs Duckworth & Co. will shortly publish a monograph of British wood-lice, 

 containing plates with enlarged figures of all our species. 



