1912] Stomoxys Calcitrans Linn. 427 
and the one dorsal to this, which is the thoracic intestine. 
s. St., the sucking stomach. 7., the abdominal intestine. m. t., 
the junction of the abdominal intestine and the proctodeum, 
at which point the Malpighian tubes enter. 7., the rectum. 
a., the anus. 
SHER. 
Fig. 2. Stomoxys calcitrans L. Semi-diagrammatic view of 
longitudinal section showing alimentary canal. 
The food canal of the proboscis was described earlier in this 
paper, and this leads to a sausage-shaped tube, which has 
chitinous, and spirally thickened walls, and which is plainly 
seen in the membranous cone when the proboscis is extended 
for feeding. (Plate XXXIV, Figs. 2 and 4, g.) This, in turn, 
opens into the pharynx, which is roughly triangular in shape, 
having its upper edges drawn out into chitinous projections as 
muscle attachments. The cesophagus, on emerging from the 
pharynx, is wide and flattened, but soon becomes narrower 
and assumes a cylindrical form. It passes slightly forward and 
upward, turns abruptly backward through the brain and into 
the thorax, where it enters the ventral, anterior part of the 
proventriculus. The proventriculus is situated in the anterior 
third of the thorax, and, when seen from above, is a delicate 
white sac, circular in outline. It is roughly the shape of a mush- 
room, with its convex surface upward. The intestine arises 
from its posterior upper surface, while the cesophagus enters 
the ventral surface. Slightly posterior to this, again, on the 
ventral surface, the duct of the sucking stomach arises. 
During its course through the thorax the intestine is prac- 
tically of uniform thickness, but at about the point where it 
passes over the sucking stomach it becomes thicker, its walls,. 
