are commonly called millipedes or thousand-legs. Their bodies may be either 

 cylindrical or flat and the chitin is usually reinforced with lime, as in the Crus^ 

 tacea. They are protected from many of their natural enemies by the presence 

 of ''stink glands", which in some forms are said to be so powerful that collectors 

 may utili2,e one or two in a jar as an efficient, emergency "killing bottle" for 

 other forms. They are generally herbivorous and some of them have become 

 serious greenhouse pests, eating the roots of plants. 



The Chilopoda or centipedes are mainly carnivorous and many of them 

 possess poison fangs. The larger, tropical species can inflict wounds that are 

 dangerous even to man. Their internal anatomy shows them to be more ad' 

 vanced than the Diplopoda and probably more nearly related to the insects than 

 they are to the millipedes. The fossil record also indicates that they are of 

 more recent origin than the millipedes, for they are first found in any quantity 

 as fossils in the Oligocene amber. 



KEY TO THE ORDERS OF MYRIAPODA 



1. With branched antennae; animals very small 



Pauropoda 

 Antennae not branched 2. 



2. With two claws on the end of each leg; animals very small 



Symphyla 

 With one claw on the end of each leg; animals occasionally minute 3. 



3. Opening to reproductive organs near the posterior end of the body; male 



gonopods (feet modified for copulation) inconspicuous or absent; with 

 one pair of legs to most of the dorsal plates, except in one genus with 

 very long legs, which has two 



Chilopoda Centipedes or Hundred Legs 

 Openings to reproductive organs near the anterior end of the body; with 

 one or both pairs of legs on the seventh segment of the male modified 

 for reproduction; most of the segments with two pairs of legs in the 

 adult 



Diplopoda Millipedes or Thousand Legs 



KEY TO THE COMMON GENERA OF PAUROPODA 



1 . Body over three times as long as wide 

 Pauropus Lubbock 

 Body less than three times as long as wide 

 Eury pauropus Ryder 



KEY TO THE COMMON GENERA OF SYMPHYLA 



L Dorsal plates rounded or emarginate behind; first pair of legs evident 

 Scutigerella Ryder 



216 



