WNf. A. KEENER. 



EXPLANATION OF PLATE II. 



FIG. 8. Reconstructed drawing of anterior stigma, h., hypodermis; te., 

 tracheal epithelium; /., tsenidia; c., cuticle; rp., reticulated plug; inv., invagination 

 of cuticle. X 200. 



FIG. 9. Transverse section of trachea through level indicated by arrow 9. 

 It shows the secondary invagination with its cuticular core inv., rp., reticulated 

 plug; te., tracheal epithelium. X 500. 



FIG. 10. Part of trachea in the transitional zone between the reticulated plug 

 and the tsenidia of the trachea, r., reticulated chitin arising from the denser layer 

 of chitin; te., traceal epithelium. X 1,500. 



FIG. n. Part of wall of trachea. /., tsenidia; te., tracheal epithelium; tl., 

 tracheal lining. X 1,500. 



