EMBRYONIC DEVELOPMENT OF THE MxlNTID 



235 



ment. X 65. B, the indusium, sagittal section, at a stage corresponding to 

 those of figures 7 and 8. The dorsal organ is forming. X 127. C, the dorsal 

 organ in sagittal section at a slightly later stage. The amnion covering the 

 anterior yolk is yet to be added. This stage is figured in surface view in figure F. 

 The indusium seems to have a definite function for the first time in its accumula- 

 tion of a large amount of serosal protoplasm for ingestion X 144. E, the indusium 

 in cross section. Same stage as figure C X 100. E, cross section through the 

 posterior portion of the serosal contraction organ of figure C. The ectoderm and 

 endoderm of the dorsal wall of the embryo are clearly distinguished. X 110. 

 F, ventral surface of th6 egg showing anterior yolk, the formation of the dorsal 

 organ and the growth of the dorsal walls of the embryo. X 21. 



A, antennal rudiment; am, amniotic protoplasm; b, second maxillary rudiment; 

 c, cephalic region; d, dorsal organ; e, eye; ec, ectoderm; en, endoderm;/, lateral 

 folds of serosa; h, chitinous secretion; i, indusium; ni, mesoderm; s, serosal pro- 

 toplasm; t, prothoracic limb rudiment; v, vitellophag; y, yolk; 1, chorin; ^, vitel- 

 line membrane; 3, serosa; 4, amnion. 



