406 THE INVERTEBRATA 



Class I. Apterygota (Ametabola). 



Order i. Thysanura. 



2. CoUembola. 



3. Protura. 



Class II. Pterygota (Metabola). 



Subclass I. Exopterygota (Hetero metabola). 



Order 4. Orthoptera. 



5. Dermaptera. 



6. Isoptera. 



7. Plecoptera. 



8. Embioptera. 



9. Psocoptera. 



10. Odonata. 



1 1 . Hemiptera ( Rhy nchota) . 



1 2 . Ephemeroptera . 



13. Mallophaga. 



14. Anoplura. 



15. Thysanoptera. 



Subclas 2. Endopterygota (Holo metabola). 



Order 16. Neuroptera. 



17. Mecoptera. 



18. Trichoptera. 



19. Lepidoptera. 



20. Coleoptera. 



2 1 . Hy menoptera . 



22. Diptera. 



23. Aphaniptera. 



24. Strepsiptera. 



Class APTERYGOTA 



Primitively wingless insects carrying on the abdomen a varying 

 number of paired appendages other than the external genitalia and 

 cerci. Metamorphosis slight or absent. 



Order THYSANURA (Bristle-tails) 



Biting mouth parts (Fig. 287); antennae many-jointed; compound 

 eyes present; abdomen of eleven segments, some or all of which bear 

 styliform appendages which probably represent the coxites of limbs 

 no longer present; anal cerci usually jointed, rarely {e.g. Japyx) in 

 the form of forceps. 



Lepisma saccharina (Fig. 302), the common "silver lish" which 

 inhabits dwellings of man, and Machilis (Petrobius) maritimus, found 



