64 R. NEWSTEAD—THE PAPATACI FLIES (PHLEBOTOMUS) 
The sucking stomach, This is a large, thin-walled pouch, connected with the 
end of the oesophagus by means of a very slender tube. It lies on the left side 
of the digestive canal, and extends distally as far as the region of the fourth 
abdominal segment. 
The mid-gut or chyle stomach. This is capable of great distention, and when 
filled with fresh blood occupies a large portion of the abdominal cavity ; but 
when such food has been partly comminuted it becomes much smaller, and can be 
easily seen as a black, elongated pouch in the anterior portion of the body. 
Malpighian tubules. There are two pairs of urinary organs, each pair being 
united at their bases, where they form a single tube, which is connected with the 
intestine immediately below the mid-gut. They are of great length, extending 
forwards as far as the first abdominal segment, where they are folded and 
doubled backwards upon themselves, and also form loops in the mid-region of the 
ventral portion of the abdominal cavity. 
The salivary glands (fig. 9). These consist of two broadly dilated or lobe-like 
acinous glands, lying one upon either side of the prothorax. The periphery of 
Eye 
Qesophagus: 
Mid- gut 
Fig. 9.—Head of Phlebotomus, showing position of salivary glands. 
these glands presents an even or smooth surface, and immediately within the 
exterior wall is a series of rather large secretory cells. The ducts leading from 
the acim unite near the mid-region of the head, forming a common duct, which 
enters the buccal cavity close to the base of the clypeus. 
The Sexual Organs of the Female. 
The ovaries occupy a variable position in the different stages of their 
development. In the early adult stages of the insect (fig. 8) they are very small, 
and are seen to extend from just behind the origin of the Malpighian tubules to 
the region of the penultimate segment of the abdomen, When fully matured 
