CONTENTS. Xxi 



Page 



JIvBERNATiON OF Insects — cofitinued. 



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 _ - - - - 555 



Some insects never torpid ----- 558 



State of the Hive-bee in winter _ _ _ - 553 



Power of resisting cold by insects in different states - - 560 



Cause of this power - . - _ - 562 



Resumption of activity _ - - - - 563 



Cause of hybernation ----- 555 



LETTER XXVn. 



Instinct of Insects - - - _ _ 568 



Nature of instinct - - . - - 568 



Definition of instinct - ... - 570 



Exquisiteness of the instincts of Insects _ . . 571 



Variations 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 - - - . 598 



