160 



EMBRYOLOGY OF INSECTS AND MYRIAPODS 



a. be 



Dorsal Lateral Ventral 



Fig. 61. — Plan of the presumptive organ anlagen for the blastoderm stage, (a) dorsal 

 side of egg, (b) left side, (c) ventral side, (abd) Abdomen aniage. (ant) Antenna anlage. 

 {eye) Eye anlage. (0 Labrum anlage. {maiid) Mandible anlage. {max 1-2) Maxillae 

 anlagen. {th 1-3) Thoracic segment anlagen. (s. oes. g) Supra-esophageal ganglion anlage. 

 (Modified from Seidel, 1935.) 



Abdomen 



Head 



jGnathos 

 Thorax 

 I Abdomen 



40hrs. 

 a 



66hrs 

 C 



51 hrs. 

 b 



luni-t = 24|j 

 Fig. 62. — Graphic representation of the shifting of the anlage regions of the left side 

 of the egg in reference to the movement of cell nuclei, (a) Blastoderm stage through (6), 

 cell aggregation to form the germ band, to (c) the completed embryo anlage. Abscissa: 

 time in hours after the two-nuclei stage. Ordinate: number of divisions from the posterior 

 pole of the egg (one division equals 24ju). {Modified from Seidel, 1935.) 



