The Development of tlie Wings of a Caddis-fly Platyphylax designatus Walk. 597 



Fig. 21. Two transverse seetions through the same wing nearly tbe same 

 age as that from which figure 20 was drawn. x 60. 



Fig. 22. View of the developing wings of a young pupa just after the Splitt- 

 ing of the last larval skin. The wings have been confined within the old larval 

 skin and have become much folded. x 10. 



Fig. 23. Somewhat older stage than the preceding, showing a still greater 

 folding of the wings. x about 10. 



Fig. 24. Transverse section of a wing of about the same stage as pre- 

 ceding figure. The wing veins have been cut transversely and obliquely and 

 are shown as light spaces in the wing. x 40. 



Fig. 25. Lateral view of a pupa. The posterior wing is somewhat covered 

 by the anterior one. Most of the antennae and legs have been removed. None 

 of the detail of the mouth parts, legs, etc. has been drawn. Head, thorax and 

 three first abdominal Segments shown. x about 5. 



Fig. 26. Dorsal view of the same pupa as preceding figure. The head, 

 thorax and four abdominal segments have been drawn. x about 5. 



Fig. 27. External view of the three thoracic segments of a recently hatched 

 larva. x 105. 



Fig. 28. External view of the meso- and metathoracic segments of a larva 

 8,5 mm long. A transverse section of the other side of this larva shows that the 

 wing disk has just formed. The two dark places on the cuticula are shown at * 

 and somewhat below can be seen the lateral margin of the dorsal plate. x 25. 



Fig. 29. External view of a small part of the meso- and metathorax, from 

 the last larval skin after it has been cast. The darkened cuticular areas over 

 the wing rudiments are seen at *. x about 10. 



Zeitschrift f. wissensch. Zoologie. CV. Bd. 39 



