212 



MILLIPEDES. 



The suborder Polydesmoidea is almost as extensive as the luloidea, its members 

 being spread over the habitable world. The largest species belonging to the genus 

 Platyrrhachus, which reach a length of several inches, occur in Tropical America 

 and the East Indies. In all, the number of segments is nineteen or twenty, or the 

 fewest amongst the Helminthomorpha. Eyes are wanting, and, as in the luloidea, 

 the segments form solid rings, owing to the fusion of the pleurae and pedal laminae 



with the terga. Secret- 

 ing pores are generally 

 present on most of the 

 segments, though some- 

 times absent in members 

 of the family Cryptodes- 

 midce. When present, 

 they are almost always 

 borne upon large plate- 

 like processes, springing 

 from the sides of the 



FLAT MILLIPEDE, Polydesmus complanatus (much enlarged). segments. In distribu- 



tion this suborder is 



cosmopolitan, the temperate forms being of small size, while some of the tropical 

 species are large and beautifully coloured. 



In habits all millipedes seem to be very similar. Although mostly 

 vegetarians, feeding on soft roots, fruits, and succulent plants, one of the smaller 

 kinds of lulidce eats worms and decaying animal matter. They occur under 

 stones, logs of wood, or in rotten tree trunks in damp places; and in tropical 

 countries come out in numbers after rain, when they may be seen crawling over 

 the ground and climbing bushes. Moisture is necessary for their existence, and in 

 captivity they freely drink water or milk. Most are slow in their movements, and 

 never trust in speed to escape. When walking the body is kept fully extended, and 

 propelled by the legs, the movements of which resemble a series of waves passing 

 up the body from behind forwards. As already stated, many forms are devoid of 

 eyes ; but even those possessing well-developed visual organs appear scarcely able to 

 do more than distinguish light from darkness. As they crawl along, every inch 

 of the road is first carefully touched by the antennae, which are tipped with a 

 sensory organ, and the creatures appear to be unaware of the presence of an 

 obstacle until the antennae have actually come into contact with it. All millipedes 

 are perfectly harmless, and may be handled with impunity; but those species 

 possessing odoriferous glands emit a disagreeable odour, due to the secretion of a 

 fluid containing prussic acid. This, no doubt, serves as a protection against birds, 

 ants, etc., to these otherwise defenceless creatures. Some birds will, however, eafc 

 them ; and in a hornbill's nest in the British Museum the plaster used to block the 

 entrance is largely composed of crushed fragments of a large Spirostreptus. Many 

 of the species which have no glands are otherwise protected. Polyxenus, for instance, 

 is studded with bristles ; while the Oniscomorpha roll themselves up into a round 

 ball, with nothing but the horny integuments exposed. In the breeding-season the 

 females of several forms make earthen nests for their eggs, working the lumps 



