9 6 



THE EMBRYOLOGY OF THE HONEY BEE 



Fig. 35. Profile drawings of eggs showing four stages in development, 

 to illustrate the relative dimensions of the egg and chorion. Outlines 

 drawn with camera lucida from fixed material. Amnion represented by 

 dotted line. A, cleavage and 'blastoderm stages ; B, Stage IV-V ; C, Stage 

 VI ; D, Stage VIII, x 41. 



and C). These spaces are invaded by the amnion. A comparison 

 of figures 35B and D shows that this second shortening of the 

 egg is not only contemporaneous with the formation of the germ 

 layers, but that it is also accompanied by the curving of the germ 

 band around the ends of the egg. It is therefore evident that the 

 shortening which takes place has principally affected the yolk, 

 and furthermore that the germ band itself has actually lengthened 

 but little, if at all, between Stages IV and VIII. The embryo 

 does not subsequently increase materially in length until immedi- 

 ately before hatching, since eggs 70-73 hours old still show spaces 

 of considerable size at their ends, between the embryo and the 

 chorion.- At the time of hatching, however, the young larva, after 

 rupture of the chorion, increases greatly in length, as shown in 

 figure XV. 



These changes in the length of the egg, with the exception of 

 the initial shortening, are not explicitly mentioned by any of the 

 previous investigators ; nevertheless, the figures of both Biitschli 



