Sub-class A, APTERYGOTA.

Order 1. _Thysanura_ (Bristle-tails).
2. _Collembola_ (Spring-tails).

Sub-class B, EXOPTERYGOTA.

Order 1. _Dermaptera_ (Earwigs).
2. _Orthoptera_ (Cockroaches, Grasshoppers, Crickets).
3. _Plecoptera_ (Stone-flies).
4. _Isoptera_ (Termites or 'White Ants').
5. _Corrodentia_
(_a_) _Copeognatha_ (Book-lice).
(_b_) _Mallophaga_ (Biting-lice).
6. _Ephemeroptera_ (May-flies).
7. _Odonata_ (Dragon-flies).
8. _Thysanoptera_ (Thrips).
9. _Hemiptera_
(_a_) _Heteroptera_ (Bugs, Pond-skaters)
(_b_) _Homoptera_ (Cicads, 'Greenfly,' Scales).
10. _Anoplura_ (Lice).

Sub-class C, ENDOPTERYGOTA.

Order 1. _Neuroptera_ (Alder-flies, Ant-lions, Lacewings).
2. _Coleoptera_ (Beetles).
3. _Mecaptera_ (Scorpion-flies).
4. _Trichoptera_ (Caddis-flies).
5. _Lepidoptera_ (Moths and Butterflies).
6. _Diptera_ (Two-winged flies)