524 



The drawing is from a section Avliich just cut the free edge of the 

 developing muscles, and tlie syncytial column has not been repre- 

 sented — sixteen-hour pupa (xl500). 



Fig. 140. Intestine of adult larva (x60). 



Fig. 141. Extremity of lateral hepatic caecum of adult larva 

 (x200). 



Fig. 142. One of the two sialivarv glands of adult larva 

 (x200). 



Fig. 143. Longitudinal section through the i-ectum of larva 

 in first instar ( x 500). Note the blindly ending midgut and rectum. 



Fig. 144. Transverse section through midgut — defaecating 

 larva. Two cells undergoing globular degeneration are seen. A 

 single replacing cell is visible (x800). 



Fig. 145. The same, four hours later (xl200). Notice tlie 

 shrinking in size of the larval cells and the proliferation of the 

 replacing cells. 



Fig. 146. The same, eight hours after defaecation ; one side 

 of the intestine is shown in section. Note the hepatic caecum, 

 and the a'ctention of larval cells in the intestinal epithelium 

 adjacent to it (xoOO). 



Fig. 147. The same, sixteen hours after defaecation. The 

 whole intestine is shown in section. Note the drawing in of the 

 hepatic caeca through the Avails of the intestine as the last remains 

 of the dead cells are forced inwards (x500). 



Fig. 148. The same. The liepatic caecum is being sucked in 

 (x-500). 



Fig. 149. Section through salivary gland, in larva about to 

 pupate (x500). Note the globular degeneration. 



Fig. 150. Portion of malpighian tube of imago (xl200). 



Fig. 151. The same, developing in defaecating larva (xl200). 



Fig. 152. Longitudinal section through junction of oesop- 

 hagus and midgut, showing the proliferating cells of the imaginal 

 disc of foregut — defaecating larva (x500). 



Fig. 153. The same, four hours after pupation. Note leuco- 

 cytes attacking the disintegrating temporary midgut (xoOO). 



Plate XXVII. 



Fig. 154. Median longitudinal section through three-hour 

 pupa, to show position of the various structures (x80). Note 

 the regenerated temporary midgut (m.g.) ending blindly at either 

 end, and filled witli the debris resulting from the degeneration of 

 the larval midgut. The oesophageal cone (o. en.) is also seen. 



Fig. 155. Longitudinal section along the junction of the 

 stomach and developing crop, gizzard, etc., after tlie front half of 

 the midgut has disintegrated — eiglit-hour pupa (x500). 



Fig. 156. The same, thirty-six hour pupa. Note diflferentia- 

 tion of crop, gizzard, and ''drum-shaped chamber" (x500). 



Fig. 157. The same, a little later, showing the opening of 

 the foregut at last into the stomach (xlOOO). 



Fig. 158. Small portion of adult oesoiDhagus ; note the deli- 

 cate spindle-sbaped cells (xlOOO). 



Fig. 159. A small portion of wall of crop, to .show the folded 

 "papery" cells (xlOOO). 



Fig, 160. Section through gizzard of adult (xlOOO). 



Fig. 161. Section along the rectum of fresh pupa, showing 

 developing rectal glands (x800). 



