MILLIPEDES 



25 



are most susceptible to desiccation and wetting tend to inhabit 

 thick leaf-htter which is proof against flood and drought, while 

 many of the lulidae and Blaniulidae penetrate deeply into the soil. 

 He also makes the interesting suggestion that calcium ions in the 

 soil water may exert a beneficial effect by limiting the permeability 

 of the epidermis. 



fO 



Fig. 8. Two types of aktograph apparatus suitable for use with 

 millipedes, each consisting of an arena or box pivoted on a knife- 

 edge along its median transverse axis. Any movement of an animal 

 along the longitudinal axis tips the arena and is recorded by a 

 lever balanced by an adjustable counterpoise and writing on a 

 revolving smoked drum. (After Gunn and Kennedy, 1937, and 

 D'Aguillar, 1952.) 



Some other aspects of the biology of the Diplopoda are worthy 

 of mention. Millipedes not infrequently occur as guests in the 

 nests of ants and termites. In Britain three species, Blaniulus gut- 

 tulatus, Proteroiulus fuscus and Polyxenus lagurus, are frequently 

 myrmecophilous (Donisthorpe, 1927)* and in the tropics several 

 species have been seen accompanying columns of army ants on the 

 march. A number of species are cavernicolous and have become 

 adapted in varying degrees to a troglodytic existence. There is 

 extensive literature on the subject. ^ 



Reports of luminous millipedes are few. One of the most striking 

 examples is Luminodesmus sequoiae, a large and handsome species 

 measuring some 40 mm in length, that inhabits the Sequoia 

 National Forest in California. Luminescence first appears on 

 hatching. It is continuous, under no voluntary control. Its source 



