CONTENTS xiii 



II. WITH EXTERNAL CHITINOUS SKELETON AND JOINTED LIMBS. 



II. Phylum : Arthropoda ... ... ... ... ... ... 307 



t 



(a) BREATHING BY AIR-TUBES; BODY CONSISTING OF THREE DISTINCT 

 PORTIONS HEAD, THORAX, ABDOMEN ; THREE PAIRS OF LEGS ; 

 GENERALLY TWO PAIRS OF WlNGS. 



CLASS I.: INSECTS ... ... ... ... ... 310 



ORDER I. 

 II. 

 III. 

 IV. 

 V. 

 *, VI. 

 VII. 

 VIII. 

 IX. 



SCALE-WINGS ... ... ... ... ... ... 318 



SHEATH-WINGS ... ... ... ... ... 339 



HOOK-WINGS ... ... ... ... ... ... 358 



Two-WiNGs ... ... .. ... ... ... 375 



NET-WINGS ... ... ... ... ... ... 332 



LONG-BEAKS ... ... ... ... ... ... 335 



STRAIGHT WINGS ... ... ... ... ... 391 



FALSE NET-WINGS ... ... ... ... ... 399 



NO-WINGS ... ... ... ... ... 403 



(6) BREATHING BY AIR-TUBES ; BODY CONSISTING OF ONLY Two PORTIONS 

 HEAD AND TRUNK; EVERY SEGMENT OF THE TRUNK FURNISHED 

 WITH ONE OR Two PAIRS OF LEGS ; WINGLESS. 



CLASS II. : MILLIPEDES AND CENTIPEDES ... ... ... ... ... 404 



ORDER I. : CENTIPEDES ... ... ... .... ... ... 404 



,, II.: MILLIPEDES ... ... ... ... ... ... 405 



(c) BREATHING AIR; BODY USUALLY CONSISTING OF Two PORTIONS 

 CEPHALO-THORAX AND ABDOMEN ; FOUR PAIRS OF LEGS ; NO WINGS. 



CLASS III.: SPIDER-LIKE ANIMALS ... ... ... ... ... 405 



ORDER I.: TRUE SPIDERS ... ... ... ... ... 405 



,, II.: HARVEST SPIDERS ... ... ... ... ... 411 



III.: SCORPIONS ... ... ... ... ... ... ill 



IV.: BOOK-SCORPIONS ... ... ... ... ... 411 



V.: MITES 412 



(d) BREATHING BY GILLS (OR ONLY THROUGH THE SKIN) ; ALMOST EXCLU- 

 SIVELY AQUATIC. 



CLASS IV.: CRUSTACEA ... ... ... ... ... ... ... 412 



GROUP I. THORACOSTRACA (PROVIDED WITH CARAPACE). 

 ORDER I.: TEN-LEGGED CRUSTACEA ... ... ... ... 413 



,, II.: MANTIS -SHRIMPS ... ... ... ... ... 422 



GROUP II. ARTHROSTRACA (WITHOUT CARAPACE). 

 ,, III.: SAND AND SHORE HOPPERS ... ... ... ... 423 



IV.: WOOD-LICE, ETC. ... ... ... ... ... 423 



