f^,, 



CLASSIFICATION 



few segments (Anajapyx) or represented by a pair of forceps (Japyx). 

 Integument thin; scales present or absent. Active and terrestrial, 

 "bristletails." Examples, Campodea (Fig. 10), Japyx, Machilis, 

 Lepisma (Fig. u), Anajapyx (Fig. 7). Some three hundred species are 

 known. 



2. Collembola. No metamorphosis. Eyes ocelliform, not more 

 than eight on each side, often fewer in number or absent. Antennae 

 short, of four segments in most genera; five or six in a few genera. 

 Mouth parts entognathous and typically mandibulate, with occasional 

 secondary suctorial modifications. Wings invariably absent. Tho- 



FIG. 10. Campodea. Length, 3 mm. 



FIG. ii. Lepisma. Length, 10 mm. 



racic segments simple and similar, or pro thorax reduced. Body cylin- 

 drical or globular. Ventral tube and furcula usually present, sometimes 

 rudimentary. Integument delicate; scales present in some genera. 

 Small or minute terrestrial insects, " springtails. " Examples, Achorutes 

 (Fig. 12), Sminthurus (Fig. 13).^ About nine hundred species have 

 been described. 



Under the term Apterygota the Thysanura and Collembola, as primi- 

 tively wingless insects, are conveniently distinguished from all other 

 insects, or Pterygota. 



3. Orthoptera. Metamorphosis direct. Eyes well developed. 

 Antennae usually filamentous, shorter or much longer than the body, 

 multiarticulate. Mouth parts mandibulate. Pronotum usually large 



