Glands or Organs of Secretion. 71 
it leaves the duct it changes instantly into the gossamer 
thread. Bees and wasps use this saliva in forming their 
structures, With it and mud some wasps make mortar; 
with it and wood, others form their paper cells; with it 
and wax, the bee fashions the ribbons that are to form the 
beautiful comb. As will be seen later, these glands are 
very complex in bees and the function of the secretion 
very varied in both composition and function. 
Lining the entire alimentary canal are mucous glands. 
which secrete a viscid fluid that keeps the tube soft and 
promotes the passage of food. 
The true stomach (Fig. 21, s, 4), is very muscular; and 
often a gizzard, as in the crickets, where its interior is lined 
with teeth. The interior of the stomach is glandular, for 
secreting the gastric juice which is to liquify the food, that 
it may be. absorbed, or pass through the walls of the canal 
into the blood. Attached to the lower portion of the stom- 
ach are numerous urinary tubes (Fig. 21), though Cuvier, 
and even Kirby, called these bile tubes. Siebold thinks some 
of the mucous glands secrete bile, and others act as a pan- 
creas. 
The intestine when short, as in larve and most carnivora, 
is straight and but little, if any, longer than the abdo- 
men, while in most plant-eaters it is long and thus zig- 
zag in its course. It is a very interesting fact that the 
alimentary canal in the larva, may be wholly shed at the 
time of molting. Strange as it may seem, the fecal pel- 
‘lets of some insects are beautiful in form, and of others 
pleasanttothe taste. These fecal masses under trees or bushes 
often reveal the presence of caterpillars. I find my children 
use them to excellent purpose in finding rare specimens. 
In some caterpillars they are barrel-shaped, artistically 
fluted, of brilliant hue, and if fossilized, would be greatly 
admired, as have been the coprolites—fossil feces of higher 
animals—if set as gems in jewelry. As it is, they would 
form no mean parlor ornament. In other insects, as the 
Aphides or plant-lice, the excrement, as well as the fluid 
that escapes from the general surface of the body, the anus, 
or in some species from special tubes called the nectaries, 
is very sweet, and in absence of floral nectar will often 
