CENTIPEDES AND MILLIPEDES 



369 



MYRIOPODA 



Centipedes. 

 Chilopoda. 



Carnivorous. 

 Poisonous. 

 Body usually flat. 



One pair of appendages to 

 each segment. The stigmata do 

 not correspond in number to the 

 segments ; they often occur on 

 alternate segments. 



Many-jointed antennae. 

 Toothed cutting mandibles. 

 Two pairs of maxillae, usually 

 with palps. 



The first pair of legs modified 

 as poison claws. 



A single genital aperture on the 

 second last segment. 



Examples. - 



-Scolopendra. 

 Lithohius. 

 Geophilus. 



Millipedes. 

 DiPLOPODA (or Chilognatha). 



Vegetarian. 

 Harmless. 

 Body cylindrical. 



By the imperfect separation of 

 the segments, all but the first three 

 behind the head seem to have two 

 pairs of appendages each, and also 

 two paired ganglia, and two pairs 

 of stigmata (tracheal openings). 



Seven-jointed antennae. 

 Broad masticating mandibles. 

 A pair of maxilla fused in a 

 broad plate, usually four-lobed. 



No poison claws. 



Genital apertures open an- 

 teriorly. 



Examples. — Julus. 



Polyxenus. 

 Glomeris. 



In the order Symphyla {Scolopendrella) there are not more than 

 twelve segments, and there is only one pair of tracheae, which open on 

 the head. Scolopendrella is in several ways hke the primitive insects 

 known as Thysanura. In the order Pauropoda {Pauropus) there are 

 ten segments, and the antenuce are branched. 



Third Class of Tracheata Antennata.— Insecta 



Insects occupy a position among the backboneless 

 animals like that of birds among the Vertebrates. The 

 typical members of both classes have wings and the power 

 of true flight, richly aerated bodies, and highly developed 

 respiratory, nervous, and sensory organs. Both are very 

 active and brightly coloured. They show parallel differ- 

 ences between the sexes, and great wealth of species within 

 a narrow range. 

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