PLATE X 



Figure 1. The proboscis of Philaetnatomyia insignis, drawn from 

 a cleared preparation. Compare with figure 1, Plate 

 VIII, noting the increase in proportionate length of 

 the haustellurn, and the increase in the area of its wall 

 which is chitinized. The simile mentioned on page 39 

 is realized by imagining that the foot is inserted from 

 left to right between the two posterior cornua, 

 p.c. x 66. 



Figure 2- A section through the lower part of the haustellurn of 

 Philaeinatoinyia insignis. ha., haematocoelic space. 

 The tracheae, not shown in the drawing, are very small 

 at this level, l.sl.g., labial salivary gland, similar to 

 that of Musca. x 650. 



Figure 3. A section through the lower end of the proboscis 

 of Lyperosia minuta. x 755. 



Figure 4. A section through the rostrum of Philaematomyia 

 insignis, showing the pharynx and its muscles. The 

 tracheal sacs are contracted *as a result of shrinkage in 

 fixation, a.w., the anterior wall of the rostrum, here 

 composed of membrane. The section is below the 

 level of the anterior arch of the fulcrum, to which this 

 membrane is attached, x 650. 



