{ { 1. Primæval winged { M.I. } { { _Archiptera_ { A.A. } { { } { I. { 2. Gauze-winged { M.C. } A. { Biting Flies { _Neuroptera_ { A.A. } { { } =Flies= { _Mordentia_ { 3. Straight-winged { M.I. } =with Chewing= { { _Orthoptera_ { A.D. } =Mouths= { { } { { 4. Beetles { M.C. } +Masticantia+ { { _Coleoptera_ { A.D. } { { { II. { 5. Skin-winged { M.C. } { Licking Flies { _Hymenoptera_ { A.A. } { _Lambentia_ { } } } { { 6. Half-winged { M.I. } { III. { _Hemiptera_ { A.A. } B. { Stinging Flies { } =Flies= { { 7. Tway-flies { M.C. } =with Sucking= { _Pungentia_ { _Diptera_ { A.D. } =Mouths= { { +Sugentia+ { IV. { 8. Butterflies { M.C. } { Sipping Flies { _Lepidoptera_ { A.A. } { { { } { _Sorbentia_ { { } _Note._—The difference in the metamorphosis or transformation and in the development of the wings of the eight individual orders of Flies is also specified by the following letters: M.I. = Imperfect Metamorphosis. M.C. = Perfect Metamorphosis. (Compare Gen. Morph. ii. p. 99.) A.A. = Equal wings (fore and hinder wings are the same, or differ but little). A.D. = Unequal wings (fore and hinder wings very different in structure and texture, occasioned by strong differentiation). CHAPTER XX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. III. VERTEBRATE ANIMALS.