Rectal Trachea! Gills. 225 



imiscle lall kinds ofi : ni =^ Malpighian tubules; O = Oesophagus; R = 

 rectum; RQ ^ rectal tracheal gill; S = lateral tracheal trunk; Sp ■= 

 dorsal thoracica! spiracle; t =^ trachea; tb = tracheal branch; V = 

 ventricle or stoinach : Vis = visceral tracheal trunk. 



1. Exuviae of the last iiN'mph. ET = exuviae of trachii ; EG == 

 exuviae of gills. 



2. Gross section trough the rectum of a füll grown nymph, showing 

 the arrangement of gills. Leitz. Obi. 1 : Oc. 2. 



3. Two gills; the arrow denoting the direction in which the section 

 of Fig. 4 is niade. Leitz. Obi. 3: Oc. 1. 



4. Transverse section of the same. Obi. D: Oc. 2. 



5. Epithelial cushion of the same, more enlarged. Zeiss. Apochr 

 4 mm: Comp. Oc. 8. 



6. Cells of the same in tangential section (drown from detached 

 cushion I. Zeiss. Apochr. 4 mm: Comp. Oc. 8. 



7. Epithelial cushion. Zeiss. Obi. D: Oc. 2. 



8. Alinientary canal and trachii of an imago ready to emerge 

 itrachii of the left side removedi. 



9. Median longitudinal section of the same; note the cushion cells 

 among the exuviae of gills. Leitz. Obj. 3: Oc. 2. 



10. Remaining gills with detached epithelial cushion. lECi. Zeiss. 



Apochr. 4 mm: Comp. Oc. 8. 



Hind instione with trachii (trachii of the left side omittedl, of 



an immature imago. 



Median longitudinal section of the same. Leitz. Obj. 3: Oc. 2. 



Hind intestine of a mature imago. 



A cross section of the same through position where the brown 



spots lie. Leitz. Obi. 3: Oc. 2. 

 IS. A Single fat cell. Zeiss. Apochr. Homol. Im. 2 nun : Comp. Oc. 12, 

 All the figures are reduced about V.v 



