20 Journal New York Entomological Society. [Voi.viu. 



Fig. l6. Section of tlie wing-bud in frontal section of larva (fifth stage). 

 Fig. 17. Section of wing-bud in cross section of larva cut in a different plane 

 than the one represented in Fig. 14 (fifth stage). 



EXPLANATION OF PLATE IlL 



Fig. iS. Wing-butl in cross section of larva just before spinning cocoon. 



Fig. 19. Wing-bud in cross section of larva just spinning cocoon. 



Fig. 20. Wingbud in cross section of larva just in cocoon. 

 Ant oilier is io. 



Fig. 21. Section of wing-bud in cross section of larva before the proliferation ot 

 the trachea. 



Pieris rapic. 



Fig. 22. Pre})ual wing dissected out for direct observation. 



Fig. 23. .Section of the wing-bud in the fifth larval stage just before hanging up 

 for the pupa stage. 



Fig. 24. Trachea and secondary tracheoles in the young pupal wing. 



Fig. 25. Cross section of prepupal wing under very high power. 



Fig. 26. Trachea and larval tracheoles in pupal wing. 



Fig. 27. Section of prepupal wing in cross section of larva. 



Fig. 28. Section through one side of prepupal wing under high power. 



EXPLANATION OF PLATE IV. 



Figures all from Pieris rafiV except Figures 34 and 37 which are from Sanninoidea 



exifiosa. 



Fig. 29. Cross section of the larva of the prepupal stage through the third 

 thoracic segment. 



Fig. 30. Cross section of very young pupal wing. 



Fig. 31. Cross section of pupal wing about four days old. 



Fig. 32. Cross section of pupal wing two days old. 



^'g- 3)Z- Trachea and larval tracheoles in pupal wing. 



Pig. 34. Cross section of young pupal wing of the peach-tree borer. 



l''S- 35- Cross section of pupal wing four days old. Section is through a vein 

 cavity. 



Fig. 36. Longi section of pupal wing two days old. 



Fig. 37- Cross section of hypodermal layer of larva with cuticle. It shows the 

 structure of the cuticle. (Peach-tree borer.) 



EXPLANATION OF PL.\TE V. 



Pieiis rapir. 



Fig. 38. Cross section of trachea in old pupal wing. 



I'ig- 39- Portion of trachea in cross section a little older than the one repre- 

 sented in Figure 38. 



