CONTENTS. xxi 



Page 

 HvBERNATiON OF Insects — Continued. 



Time of hybernation - _ - _ - 554 



Site of hybernacula - . _ - - 554 



Solitary and social hybernation - - - .^ 555 



Hybernation in several states _ _ _■ _ 555 



Torpidity produced by cold ----- 556 



Variations of torpidity ----- 556 



Some insects never torpid ----- 559 



State of the Hive-bee in winter - - . _ 558 



Power of resisting cold by insects in different states - - 660 



Cause of this power _ _ _ _ - 552 



Resumption of activity _ - - - - 553 



Cause of hybernation _ - - _ - 5(55 



LETTER XXVn. 



Instinct of Insects ----- ggS 



Nature of instinct ----- 568 



Definition of instinct • - - - - - 570 



Exquisiteness of the instincts ot Insects - . - 571 



A'ariations of instinct ----- 572 



Variations of instinct in the Hive-bee - - - - 576 



These variations not the result of reason - - . 583 



Number of instincts in Insects _ _ - - 584 



Extraordinary development of instinct in Insects - - 589 



Reason in Insects _ - « . _ 591 



Insects gain knowledge from experience - . - 596 



receive and communicate information - • - - 597 



are endowed with memory - - _ . 593 



