Food-Canal — Glands 6^ 



some insects which feed by sucking liquid food — 

 Moths, Flies and Bugs, for example — the gullet is 

 expanded just behind the mouth to form a spherical 

 sucking-pump, attached to the head capsule by 

 muscles. This draws in food and forces it back- 

 wards into the gullet, which is long and slender and 

 leads directly into the stomach, there being no gizzard, 

 as there is no solid food to be strained. In these 

 insects, just before the gullet joins the stomach it 

 gives off a large pear-shaped or spherical sac often 

 called the " sucking stomach," but now known to be 

 a reservoir for storing food ; possibly this organ 

 corresponds with the crop in the cockroach. In 

 Moths it opens out close to the forward end of the 

 stomach, but in Flies it is situated at the end of a 

 long tube (2, 4). 



In Bees (fig. 47) and Ants the gizzard of the cock- 

 roach is represented by the " honey stomach," which 

 communicates with the stomach by means of a thick- 

 walled "honey-stopper" provided internally with four 

 chitinous ridges set with fine hairs pointing back- 

 wards. These can be brought together, like the 

 teeth of the cockroach's gizzard, so as to close the 

 •passage, or separated so as to leave a cross-shaped 

 opening. By means of this stopper, solid food such 

 as pollen is separated from the honey as necessity may 

 require. 



Spittle-glands. — As mentioned above, the spittle 

 or salivary glands open into the mouth. On either 

 side of the gullet and crop may be seen a gland and 

 its reservoir (fig. 43). The gland is a thin leaf-like 

 mass, composed of two large lobes and a third much 

 smaller. The spittle, secreted by the large epithelial 

 cells of the glandular tissue is led off by tubes or 

 ducts which unite to form a duct with chitinous 

 lining, strengthened by spiral threads like the air 



