IV CONTENTS. 



IX. Monograph on the Genera and Species of the Maloco- 



stracous Family Leucosidea - - - _ page 17 



X. On the Characters of the Genus Thalassina of Latreille, 



with a Description of one Species - - - 27 



XI. On the Characters of the Genus Atya of Leach, with a 



Description of one Species - - - - - 29 



Class MYRIAPODA. 



XII. The Characters of the Genera of the Class Mt/riapodaj 



with Descriptions of some Species - - - 31 



Class ARACHNIDES. 



Xm. On tl>e Characters of tlie Class Arachmdes and of its 



Families -_--__-- 46 



XIV. On the Characters of the Genera of the Family Scor- 

 piofiidea, with Descriptions of the British Species cf 



Chelifer and Obi slum ------ 48 



Class ? 



XV. Descriptions of three Species of the Genus Phihiri'- 



diuvi of Hermann - , - - - _ 54 



Class INSECTS, 



XVI. On the Characters of the Class Insect a, and of the 

 Orders composing it- <- - - - - bl 



XVII. On the Families, Stirpes, and Genera of the Order 

 Thysanura - - - - - - - -61 



XVIII. On the Families, Stirpes, and Genera of the Order 

 Anoplura --------64 



XIX. Synopsis of the Stirpes and Genera of the Family 

 Dyticidea --------68 



XX. On the Natural Characters of four Genera which ha\e 



been confounded under the Name Silpha - - 74 



XXI. A Sketch of the Characters of the Stiq)es and Genera 



of the Family Ilisteridea ----- 76 



XXII. On the Stirpes and Genera composing the Family 

 Pselaphidea ; with the Names of the British Species 80 



