THE EXTEENAl STETJCTTIEB OF BIBDS. 



165 



Ptbeyl* op D0K8AL AND Ventral Surfaces of the Swipt, 

 (^After Nitzsch.) 

 Fig. 146. Ventral aspect. Fig.. 147. Dorsal aspect. 



I. Dorsal or spinal pteryla. 2. Humeral pteryla. 3. Femoral pteryla. 

 4. Cranial pteryla. 5. Alar pteryla. 6. Caudal pteryla. 7. Crural 

 pteryla. 8. Ventral pteryla. 



