526 



Fig. 192. Section tlirougli end of ovary (fresh pupa). Note 

 fourfold conuective tissue ingrowth (x350). 



Fig. 193. Two larval leucocytes (xl500). 



Fig. 194. Leucocyte from eight-hour pupa, showing great 

 vacuoles (xl500). 



Fig. 195. Leucocyte in eight-hour pupa, which has engulfed 

 numerous minute pieces of larval tissue (xlSOO). 



Fig. 196. Dividing leucocyte, sixteen hours before pupation 

 (xlSOO). 



Fig. 197. A leucocyte which has engulfed several large strips 

 of larval muscle (x2000). 



Fig. 198. Leucocyte that has engulfed larval tissue (x2000). 



Fig. 199. As in Eg. 197 (x200a). 



Fig. 200. '^NormaP' leucocyte, adult larva (x220O). 



Figs. 201, 202, 20S. Three leucocytes which have absorbed 

 pieces of larval muscle and are degenerating among the "wing" 

 muscles (x2000, xloOO, xloOO, respectively). 



Plate XXIX. 



Fig. 204, .a, b, c. Three gorged leucocytes which, after feed- 

 ing, have '^retired" to a cavitv of a hollow appendage — eight-hour 

 pupa (x200a). 



Figs. 205, 206. Similar leucocytes, which could not survive 

 their meal, and are disintegrating — eight-hour pupa (xl500). 



Fig. 207. A leucocyte in four and a half day pupa degen- 

 erating (xlSOO). 



Fig. 208. A leucocyte of imago, which is recovering from 

 its meal — fifty-two hour pupa (xl500). 



Fig. 209. A leucocyte from four and a half day pupa which 

 has entirely recovered (xlSOO). 



Fig. 210. A nucleus from integumental cell of defaecating 

 larva, showing crystals within the great nucleolus (x2300). 

 ~ Fig. 211. "Heart" of adult larva (x420). 



Fig. 212. Posterior end of same, showing ostia (x800). 



Fig. 213. Section through heart and adjacent structure of 

 larva tAvelve hours before defaecatiou. Note the delicate cellular 

 pericardium outside the heart. Note also the proliferating anlage 

 of dorsal abdominal glands (cf. fig. 173) (x800). 



Fig. 214. Median longitudinal section along dorsal body wall, 

 to show metamorphosing "heart." The integument and larval 

 cuticle are also shown. The small imaginal and hypertrophied 

 larval cells are easily distinguishe'd. Note especially the prolifera- 

 tion of cells along ventral portion of heart. A few leucocytes 

 0) are lying within the heart — defaecating larva (xlOOO). 



Fig, 215. The same. Numerous embryonic cells extending 

 upwards in a solid column, and overwhelming the hvpertrophied 

 larval cells (xlOOO). " ' ' 



Fig. 216. The wall of heart, showing the large larval cells 

 and small embryonic cells advancing upon them ( x 1000) — defae- 

 cating larva. 



Fig. 217. Section through dorsal body wall of larva six hours 

 after defaecatiou, showing embryonic cells at base of regenerated 

 heart tube (xoOO). 



Fig. 218. The same, in a more anterior part of the heart. 

 Note the embryonic cells enveloping the regenerated heart tube 

 <xl200). 



Fig. 219. Regenerated heart (aorta) from fresh pupa (xlOOO). 



