170 



EMBRYOLOGY OF INSECTS AND MYRIAFODS 



cut. I 



YiG, 7S.—Isotomn. Cross section of head, {cut 1, cut 2) First and second crenated mem- 

 branes, (ect) Ectoderm, (il) Inner layer. 



cui.l 



Fig. 74.— Isotoma. Cross section of posterior end. {am. ser) Amnioserosa. {cut) 

 Crenated membranes, {do) Dorsal organ, {ect) Ectoderm, {gc) Germ cells, {il) Inner 

 layer. 



