298 ARTHUR D. WHEDON. 



PLATE I. 



Fig. i. Extended labium of the larva, viewed from below and showing the 

 muscles and tendons as seen through the transparent skeleton. X 6. 



FIG. 2. Retracted labium of the larva as it appears a short time before the 

 insect transforms. Ventral view of head and dorsal view of the labium. The 

 hypo-pharynx, bases of the maxillae and other structures are shown surrounded 

 by the loose larval skeleton. X 9. 



FIG. 3. A ventral view of the same labium shown in Fig. 2. X 9. 



FIG. 4. Extended and flattened labium of the adult in ventral view showing 

 the muscles. X 9. 



FIG. 5. Ventral view of the mentum of the adult. The labium in this and the 

 next two figures is in normal condition, not flattened out. The muscles and their 

 attachments are drawn in one half only in order to show the skeletal features on 

 the opposite side. X 9- 



FIG. 6. Ventral view of the submentum of the specimen shown in Fig. 5. 

 Other conditions the same. X 9. 



FIG. 7. A view into the cup-like labium of the adult from the dorsal aspect. 

 The muscle relations are shown, and in addition the mechanism of the end hooks 

 and the median lobe. X Q. 



