Volume VIII. April, l8gS- Number I. 



JOURNAL 



MORPHOLOGY. 



A CONTRIBUTION TO INSECT EMBRYOLOGY. 



WILLIAM MORTON WHEELER. 



TABLE OF CONTENTS. 



Page 



Introduction 



I. The embryonic development of the Locustidas 3 



1. The ovipositio7i of Xiphidhtjn ensiferum, Scud. 3 



2. The formation of the Xiphidium embryo and its backward passage 



through the yolk 5 



(a) Description of surface changes beginning with the completed 



blastoderm e 



(b) The indtisiiim (prcEoral organ) in section 12 



3. The development of the embryo from the time of its reaching the 



dorsal surface of the yolk to revolution 18 



4. Variations in the development of the indusinm 25 



5. The revolution of the embryo 27 



6. The stages intervening between revolution and hatching. 29 



7. The development of Orchelimum vtilgare 35 



II. Gastrulation in the Orthoptera 36 



III. The indusium and its homologues in the Arthropoda 55 



IV. General consideration of the embryonic envelopes and revolution of 



the insect embryo 59 



1. The amnion and serosa 59 



2. The yolk 64 



3. Blastokinesis 67 



4. The elimination of the embryonic envelopes 78 



