CONTENTS xill 

 II. With External Chitinous Skeleton and Jointed Limbs. 



PAGE 



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



(a) Breathing by Air-tubes; Body consisting op Three Distinct 

 Portions — Head, Thorax, Abdomen ; Three Pairs of Legs ; 

 generally Two Pairs of Wings. 



Class I. : Insects ... ... ... ... ... ... ... 310 



Order I.: Scale- Wings ... ... ... ... ... ... 318 



II. : Sheath-Wings ... ... ... ... ... 339 



, III.: Hook-Wings ... ... ... ... ... ... 358 



IV.: Two-Wings ... ... .. ... ... ... 375 



V.: Net-Wings ... ... ... ... ... ... 382 



VI.: Long-Beaks ... ... ... ... ... ... 385 



, VII. : Straight Wings ... ... ... ... ... 391 



, VIII. : False Net- Wings ... ... ... ... ... 399 



, IX.: 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 Am; 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 ... ... •■• ••■ ••• ••■ *H 



„ 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 



