APPENDIX 837 



CLASS 2. DIPLOPODA. Millipedes. Every other body segment reduced, especially 



dorsally. About eight orders. 

 CLASS 3. PAUROPODA. Similar to millipedes. Small, eyeless, with branched 



antennae. Two orders. 

 CLASS 4. SYMPHYLA. Small, eyeless. Mouth parts and legs similar to those of 

 insects. One order. 

 SUPERCLASS 2. HEXAPODA. Adults with three pairs of legs. One class, Insecta. 

 GROUP 1. APTERYGOTA. Primitively wingless, very little metamorphosis. 

 Orders 1 and 2 are often placed in a separate class. 

 Order 1. Thysanura. Silverfish, firebrats. 



Order 2. Entotrophi. Similar to the Thysanura but lack scales on body. 

 Order 3. Profura. Lack both eyes and antennae. Often considered to 



be a class. 

 Order 4. Collembola. Springtails, snowfleas. Often considered to be a 

 class, sometimes a superclass. 

 GROUP 2. PTERYGOTA. With wings, although numerous species have sec- 

 ondarily lost the wings. When the above groups are separated as 

 three classes, this group forms a fourth and is usually called 

 Insecta. 

 Subclass 1. Paleoptera. Wings held stiffly out at the sides. Five extinct 

 orders and: 

 Order 1. Odonata. Dragon flies and damsel flies. 

 Order 2. Ephemeroptera. .Mayflies. 

 Subclass 2. Neoptera. Wings fold back when at rest. 



Superorder 1. Exopterygota. \\'ingbuds external, metamorphosis in- 

 complete. Five extinct orders and: 

 Order 1. Plecoptera. Stoneflies. 

 Order 2. Orfhopfera. Praying mantids, walking sticks, grasshoppers, 



crickets and katydids. 

 Order 3. Blattaria. Cockroaches. 

 Order 4. Isoptera. Termites. 

 Order 5. Dermaptera. Earwigs. 



Order 6. Embioptera. Somewhat like termites and earwigs. 

 Order 7. Thysanoptera. Thrips. 

 Order 8. Psocoptera. Book lice. 

 Order 9. Mallophaga. Birdlice or biting lice. 

 Order 10. Anoplura. Sucking lice. Pediculus, Phthirus, etc. 

 Order 11. Hemipfera. True bugs, plant lice, cicadas, Rhodnins. 

 Superorder 2. Endopterygota. Wingbuds internal, metamorphosis com- 

 plete. 

 Order 1. Neuropfera. Lacewings, ant lions, etc. 

 Order 2. Mecoptera. Scorpion flies. 

 Order 3. Trichoptera. Caddis flies. 

 Order 4. Lepidoptera. Butterflies and moths. 

 Order 5. Coleoptera. Beetles. 



Order 6. Sfrepsiptera. Small, with vestigial anterior wings. 

 Order 7. Hymenoptera. Sawflies, ants, bees (Apis), wasps, etc. 

 Order 8. Diptera. True flies, gnats, mosquitos, Dermatobia, etc. 

 Order 9. Siphonaptera. Fleas. Xenopsylla. 



Of several extinct arthropod groups of imcertain affinities, the Archaeostraca (four 

 orders) are probably a subclass of the class Crustacea. The Homopoda (four orders), 

 with two pairs of antennae followed by biramous limbs, can be considered a separate 

 class in the subphylum that includes the Crustacea. The Xenopoda (one order) are 



