116 ZOOLOGY. 



Mygale avicularia of South America is known to seize 

 small birds and suck their blood. There are probably 

 about eight hundred species of spiders in North America; 

 their colors are often brilliant, and sometimes, from the 

 harmony in their coloration with that of the flowers in 

 which they hide or the leaves on which they may rest, 

 elude the sight of insectivorous birds. John Burroughs, in 

 his "Pejiacton," says that one sunny April day his "atten- 

 tion was attracted by a soft, uncertain purring sound " made 

 by little spiders travelling about over the leaves. 



Class VI. — Insecta. 



General Characters of Insects. — Winged insects have a 

 separate head, thorax, and abdomen. They have comj^ound 

 as well as simjjle eyes, two pairs of wings, and three pairs 

 of thoracic legs. There are sixteen orders. 



Ordehs op Insects. 



1. AVingles3, of len with a spring, r/iysarawra.- Spring tails, etc. 



2. Fore wings minute, clyti'a \i\ie,.Dermaptera : Earwig. 



3. Wings net veined; fore wings 



narrow; bind wings folded. .Orthopiera: Locusts, Grasshoppers. 



4. Four net-veined wings; mouth- 



parts adapted for biting Platyptera : White Ants, Bird-lice. 



5. Wings net- veined, equal Odonata: Dragou-flies. 



6. Wings net-veined, unequal. .. .Pfccto^rera.' Mayflies. 



7. Mouth beak-like, but with palpi r/iy^ano^feru.' Thrips. 



8. Mouth-parts forming a beak 



for sucking; no palpi Hemiptera: Bugs. 



9. Wings net-veined ; metamor- 



phosis complete Neuropiera : Lace-winged Fly, etc 



10. Wings long and narrow MecopUra : Panorpa. 



11. Wings not net-veined Trichoptera : Caddis-tiy. 



12. Fore wings sheathing the hind- 



er ones Coleoptera : Beetles. 



13. Wingless, parasitic SipJionaptera : Flea. 



14. One pair of wings DipUra : Flies. 



15. Four wings and body scaled. . Lepidopto-a : Butterflies. 

 J.6. Four clear wings; hinder pair 



small; a tongue Hymeivrpteva : Bees, Wasps, etc. 



