OR, MANDAI< OP THE ApiARY. 89 



as in our own class of animals, varies very much in leng^th and 

 complexity, as the hosts of insects vary in their habits. As in 

 mammals and birds, the length, with some striking- exceptions, 

 varies with the food. Carnivorous or flesh-eating insects have 

 a short alimentary canal, while in those that feed on vegetable 

 food it is much longer. 



The mouth I have already described. Following this (Fig. 

 27) is the throat or pharynx, then the oesophagus or gullet (Fig. 

 36, o), which may expand, as in the bee, to form the honey- 

 stomach (Fig. 36, hs), may have an attached crop like the 



Fig. 36. 



Cross Section of Ileum, after 

 jSckiernenz. 



Alimentary Caiial of Soney-Bee, modified, from Wolff. 



CEsophagus. ^ni Stomach-mouth. 

 Im Honey-stomach. n True stomach. 



c Urinary tubes. i Small intestine or ileum. 



rg Rectal glands. r Large intestine or rectum. 



chicken, or may run as a uniform tube, as in the human body, 

 to the true stomach (Fig. 36, s). Following this is the intes- 

 tine — separated by some authors into an ileum (Fig. 36, i), and 

 a rectum which ends in the vent or anus. 



The entire alimentary canal, except the stomach, is devel- 

 oped from the ectoderm, or skin derm, and all is shed in 

 molting. The stomach, often called the mid-stomach, to dis- 

 tinguish it from the fore and hind, is derived from the endo- 

 derm, and is not molted. Connected with the mouth are 

 salivary glands (Fig. 58, 59), which are structurally much like 



