Lepismataidea Machilaidea 81 



a similar and long median cerciform appendage; the second to 

 the seventh ventral segments with single-jointed, marginal styles 

 and eversible sacs; eighth and ninth ventral segments of female 

 with paired short, conical, egg-laying appendages; mouthparts 

 free, their tips visible. 



ORDER LEPISMATOIDEA. 



(ZYGENTOMA.) 



Rather small, very active, wingless, terrestrial forms, with the 

 body narrow, flattened and gradually attenuated posteriorly; 

 body always clothed with scales; eyes small, not approximate; 

 consisting of separated ocelli; tergites weakly developed, but the 

 pleurites and sternites strongly so; pro thorax as large and usually 

 much larger than the mesothorax; tarsi two- join ted; two pairs 

 of thoracic and eight pairs of abdominal spiracles; no power of 

 springing. 



(Lepisma [L. saccharina. Bristle-tail), Gastrotheus].) (PL 16, figs. 378, 387). 



LEPISMATIDJE 



ORDER MACHILOIDEA. 



(ARCHEOGNATHA.) 



Rather small active wingless, terrestrial forms, with the body 

 convex above and somewhat compressed, gradually tapering pos- 

 teriorly; body clothed with scales; eyes very large, meeting or 

 nearly so; tergites strongly developed, extending to the under side 

 of the body, the pleurites and sternites greatly reduced; prothorax 

 smaller than the mesothorax; tarsi three- jointed; two pairs of 

 thoracic and seven pairs of abdominal spiracles; insects capable 

 of springing. 

 (MSchilis.) MACHILID^E 



CLASS CAMPODEOIDEA. 



(DIPLURA.) 



Small, slender, wingless insects incapable of springing and of 

 sluggish habits; body never clothed with scales; antennae usually 

 many jointed; eyes absent; abdomen consisting of eleven segments, 

 the last segment either more or less covered by the preceding 

 or fused with it; no ventral tube, but the first to the seventh or 

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