538 Prof, E. A. Minchin. Report on the [Aug. 17, 
the Malpighian tubules (*, fig. 3), so that from this point the gut must be 
regarded as proctodeum. The eleventh limb (11) runs from right to left in 
a semicircular curve occupying the fifth and sixth segments. From the 
origin of the Malpighian tubules to the end of. the eleventh limb the gut is of 
small calibre, and may be called the ileum. The succeeding portion is thicker, 
and may be called the colon. It lies in the fifth and sixth segments, and 
forms the twelfth and thirteenth limbs (12, 13), both short and sharply bent 
one on the other. The ileum and colon lie dorsally in the body, and the colon 
passes into the capacious rectum (R.), which has four rectal glands (fig. 5, 7. gl.) 
each supplied by a bunch of small trachee. ‘ 
The appendages of the digestive tract are the salivary glands, the sucking 
stomach, and the Malpighian tubules. 
The salivary glands (fig. 2, S. G.) commence, starting from their distal ends, 
as two long tubes, much coiled, and occupying a very superficial dorsal 
position in the abdomen on each side of the heart, above the alary muscles. 
Very transparent in the fresh condition, the salivary glands become glistening 
white in colour when put in alcohol. Only trachez and fat-body come: 
between them and the dorsal body-wall. The coils of the tubes extend back 
as far as the fourth or fifth abdominal segment, but the distal extremity of 
the gland may lie further forward than this. With many twists and turns 
the tubes run forward to the waist and then pass into the thorax, at the same 
time diminishing rapidly in calibre, straightening out their coils, and 
descending to the ventral side of the body. From this point the salivary 
gland becomes the salivary duct (figs. 1 and 2, 8S. D.). The two ducts run a 
parallel course through the thorax, on a level with the duct of the sucking 
stomach, and on each side of it, passing under the stomach and above the 
thoracic ganglion (figs. 1 and 2). When they reach the neck, the salivary 
ducts become so extremely attenuated that their course through the head is 
very difficult to follow. As they enter the neck the ducts curve over towards 
each other, and pass under the connective nerve-band, thus parting company 
from the cesophagus, which passes above the connective. The ducts pass 
under the brain and then under the pharynx. | 
If the head of a fly be examined from below, there will be found, 
immediately behind the bulb of the proboscis, an area covered by soft 
flexible integument, which recalls the soft skin at the base of a parrot’s 
beak, and has a similar function, that is to say, to allow free play for the 
movements of the proboscis. When the proboscis is bent down, in the 
attitude it assumes when the fly is drawing blood, the soft skin forms a 
fold over the bulb, and when the proboscis points forward, in the attitude 
of repose, enclosed in the sheath formed by the two palpi, then the soft 
