occupies the dorsal gutter of the labium, and is kept in this position 
by the pressure of the lateral arms of the labruin which stretch over 
on either side for a short distance (figs. 2Q, 30). 
In section near the tip it appears as a chitinous hoop, formula 
circle complete for about seven eighths of its circumference. At firs 
the hoop has near the apex on each side a little tubercle, and stretching 
across between these tubercles is a thinner chitinous membrane 
completing the tube dorsally. As we get nearer the base there is a 
distinct separation in the walls of the chitinous ring in the position 
where the tubercles first appear, so that a cavity now exists in the 
sides (fig. 29). This goes on increasing till eventually we have the 
chitinous circular inner tube lying within a sausage-shaped outer 
covering, forming a projecting angle on either side (fig. 30, £). 
At its base the ventral wall of the hypopharynx becomes fused 
with the bottom of the labial gutter. The beginning of this is shown 
m 3 °' This proceeds until the process is complete on either side 
I he fused wall is then absorbed, and thus permits of the inner 
(| Oropharyngeal) tube escaping through ventrally. At the same time 
! e dorsal wall of the hypopharynx becomes fused with the ventral 
-alf of the epipharynx, forming now the pharyngeal tube (fig. 3') 
", If *1 !\ d ° rsal Iialf of llie epipharynx fuses laterally with the sides 
3 ,um ’ so ^ lat ^ ie w hole of the epipharynx and hypopharynx 
• exce Pti°n of the dorsal wall of the former, have now become 
internal structures. 
MUSCULAR SYSTEM (s, i„ all the figs.) 
two lame c P ro ^ osc * s it is often possible to separate out 
These htto * aratc lllasses °f muscle which terminate in tendons ( f . 
*»e b ? hl “ d ;° the t,p ° f t,ip ^ ^- »i 
the proboscis H - 1 P ane untl1 we reach the bulbous portion of 
they arise, whi 1 ^ ^ tendons & ive P lace to the muscles from which 
the whole of th COnsist °f tw o masses filling posteriorly practically 
describe as the 1 Cntra ^ P ort ion of the bulb. These muscles we i« a ) 
the median ***■> we have on either sid> 
forming a broad 1 ° j^ e ^ utter a group of oblique muscles (•'' 
inserted into tlie '”]•’ ' U ' S ' n ^ from the chitinous integument and 
separated from it !' U ' limb ^ 2 9 )- Dorsal to this group. nIlri 
y the tendon, there is a second oblique group (* J ) 
