CLASSIFICATION OF INSECTS 49 



parts. Anterior wings usually shorter and firmer than those 

 behind, or modified into wing covers. Both pairs are some- 

 times absent. 



Order 4. Dermaptcra; Earwigs. Biting mouth parts. 

 Anterior wings small; hind wings large, but folded both 

 longitudinally and crosswise. Posterior forceps. 



Order 5. Plecoptera; Perla. Biting mouth parts. Two 

 pairs of wings or none. Larvae aquatic. 



Order 6. Ephemerida; May flies. Adult mouth parts 

 degenerate and rarely used. Fore wings large, hind wings 

 small or absent. Larvse aquatic, with biting mouth parts. 



Order 7. Odonata; Dragon flies. Biting mouth parts. 

 Two pairs of large unfolded wings. Larvae aquatic. 



Order 8. Isoptera; Termites. Biting mouth parts. 

 Wings often wanting. Social in habit. 



Order 9. Corrodentia; Book lice. Psocids. Biting mouth 

 parts, wings often wanting. 



Order 10. Mallophaga; Bird lice. Parasitic, wingless, 

 with biting mouth parts. 



Order 11. Thysanoptera; Thrips. Suctorial mouth parts. 

 Wings very narrow, often rudimentary or absent. Only 

 three or four pairs of stigmata. Concentrated nervous 

 system. 



Order 12. Hemiptem; Phylloxera, aphides, scale insects, 

 cicadas, bugs, water scorpions, lice. (Male scale insects 

 (coccidae) have complete metamorphosis.) Mouth parts 

 adapted for sucking and piercing. Two pairs of wings or 

 none. No compound eyes iu parasitic forms which are 

 degenerate in several respects. 



With Complete Metantorphosls. 



(Holometabola.) 



Biting Mouth Parts (Mandibulate). 



Order 13. Neuroptem; Ant lions, lace-winged flies. Two 

 pairs of glassy wings with many nervures. Larvie sometimes 

 aquatic. 



