( I \SSII i< \ I 



, 9 



MI I ,-. nted by ;i pair oi tnr. <-p lit pyx). 



unicnt lliin. <nl. A^ 



"bristletails." Examples, (',/;;/ /Wm (Fig. 10), Japyx, Mac/n!i\, 

 Lcjusniii ( I-'i.u. in. . I >/<//<//> v.v I I-'i^. 7). Sonic tlm-r hundred p 

 known. 



2. Collembola. No nirlainnrphn > o-llit"<n)i, Qi 



than I'i^ht on c;u h silc. often iVucr in nunil)c-r it. An: 



short, of four sc^nu-nts in most in a few g< 



Mouth parts rnto<jnathoiis and typirally mandihulatc. with D 

 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 prothorax 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. " 1 .xamples, 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 



