DIGESTIVE ORGANS OF INSECTS. 



187 



principal varieties, selected from those in which 

 the leading characters of structure are most 



strongly marked. I shall, with 

 this view, exhibit, first one of the 

 simplest forms of the alimentary 

 organs, as they occur in the 

 3Icmtis religiosa, (Linn.) which 

 is a purely carnivorous insect, 

 belonging to the order of Orthop- 

 tera. Fig. 317 represents those 

 of this insect, freed from their 

 attachments, and separated from 

 the body. The whole canal, as 

 is seen, is perfectly straight : it 

 commences by an oesophagus 

 (()), of great length, which is 

 succeeded by a gizzard (g) ; at 

 the lower extremity of this organ 

 the upper hepatic vessels (b, p.), 

 eight in number, and of consi- 

 derable diameter, are inserted : then follows a por- 

 tion of the canal (d), which may be regarded either 

 as a digesting stomach, or a chyliferous duodenum : 

 farther downwards, the second set of hepatic vessels, 

 (h h), which are very numerous, but as slender as 

 hairs, are received ; and after a small contraction 

 (n) there is again a slight dilatation of the tube (c) 

 before it terminates. 



The alimentary canal of the Cicinclela campestris, 

 (Linn.) which preys on other insects, is represented 

 in Fig. 318; where we see that the lower part of 

 the oesophagus (o), is dilated into a crop (p), suc- 

 ceeded by a small gizzard (g), which is provided 

 for the purpose of bruising tlie elytra, and other 



