EXPLANATION OF PLATE XIX 
I-ig. 29.—Section approximately through the middle plane of the 
proboscis, in which are seen the labrum (a), the 
hypopharynx ( b ) completely closed and interlocked with the 
labium. Here also the row-lock like appearance of the 
labial gutter is well shown and the rod-like sclerites 
have completely disappeared, x 750. 
F 'g- 30 .— Section through the bulb of the proboscis. Here the 
hypopharynx is seen fusing with the walls of the labial 
g-utter, and the large air sacs (i) have taken the place of 
the tracheal tubes (fig. 29, i\ etc.), x ; 5 o. 
S 3 • Section through the base of the bulbous portion of the 
proboscis, including the apodemes (h) of the labrum. Here 
* e wa ^ the hypopharynx has become fused with 
a rum, forming the pharyngeal tube, x 200. 
