TABLE OF CONTENTS xiii 



C. Stridulating organs of the rasping type 81 



The stridulating organs of the Acridiidae 82 



The stridulating organs of the Gryllidae and the Locustidse . 83 



Rasping organs of other than orthopterous insects 87 



d. The musical organs of a cicada v . . . . 89 



e. The spiracular musical organs 91 



/. The acute buzzing of flies and bees 91 



g. Musical notation of the songs of insects 92 



h. Insect choruses 93 



CHAPTER III 



THE INTERNAL ANATOMY OF INSECTS 94 



I. THE HYPODERMAL STRUCTURES 95 



a. The internal skeleton 95 



Sources of the internal skeleton 95 



Chitinized tendons 95 



Inyaginations of the body- wall or apodemes 95 



The tentorium 96 



The posterior arms of the tentorium 96 



The anterior arms of the tentorium 97 



The dorsal arms of the tentorium 97 



The frontal plate of the tentorium 97 



The endothorax 97 



The pragmas 97 



The lateral apodemes 98 



The furcae ^ 98 



b. The hypodermal glands 98 



The molting-fluid glands 99 



Glands connected with setae 99 



Venomous setae and spines . 100 



Androcoriia 100 



The specific scent-glands of females 100 



Tenent hairs 100 



The osmeteria 101 



- Glands opening on the surf ace of the body 102 



Wax-glands 102 



Froth-glands of spittle insects 102 



Stink-glands 102 



The cephalic silk-glands 103 



The salivary glands 104 



2. THE MUSCLES I<>4 



3. THE ALIMENTARY CANAL AND ITS APPENDAGES 107 



a. The more general features IO 7 



The principal divisions 108 



Imperf orate intestines in the larvae of certain insects 108 



