xxviii CONTENTS. 



Page 

 LUMINOUS INSECTS continued. 



Other Luminous Beetles _._.-- 506 



Lantern-flies -------- 508 



Other Luminous insects - " - - 510 



Source of their luminous property - - - - 512 



Its remote cause - - - - - -* , - 513 



Its use - - , - - - ; ^ A - 514 



LETTER XXVI. 

 HYBERNATION OF INSECTS .... - 516 534 



In the egg state -__...- 517 



pupa state - - - - - - 518 



larva state - - - - - - -518 



perfect state - - - - ^ v . - 519 



Time of hybernation - - - ,-* ... 52O 



Site of Hybernacula ------- 520 



Solitary and social hybernation - - - - - 521 



Hybernation in several states - - -- - -521 



Torpidity produced by cold - - - - - -521 



Variations of torpidity : ii , - - - - - 522 



Some insects never torpid - - - - -523 



State of the Hive Bee in winter - -524 



Power of resisting cold by insects in different states - - - 526 



Cause of this power ------ 528 



Resumption of activity ..-.-- 529 



Cause of hybernation .... - 530 



LETTER XXVIT. 

 INSTINCT or INSECTS ...--- 535 567 



Nature of instinct - - - - - - 535 



Definition of instinct - - - - - - -537 



Exquisiteness of the instincts of Insects ... -538 



Variations of instinct ------- 539 



Variations of instinct in the Hive Bee - - _ - 542 



These variations not the result of reason - - - - o49 



Number of instincts in Insects - 550 



Extraordinary development of instinct in Insects ... 5.56 



Reason in Insects - - - - - - -557 



Insects gain knowledge from experience - 562 



receive and communicate information - 564 



are endowed with memory ... - 565 



APPENDIX .-.---. 569 



