18 



ehitinous ridges and hooks, by means of which the food is 

 reduced to a finer condition before entering the stomach. 

 In certain insects, at least, a larger part of the actual 

 digestive process is jearried on in the crop, and in these 

 also, the gizzard serves as a strainer through which 

 the finer portions of the food, with digestive fluids, are carried 

 to the stomach, in which absorption takes place. The stomach 

 is a large digestive organ (Fig. 11) from which the food 

 passes to the intestine, colon, rectum, and to the anus, where 

 waste and undigested food is voided. The food canal is 

 composed of three sections, the fore-gut, mid-gut and hind- 

 gut. 



The manner of taking food also varies greatly among 

 insects. Certain insects with biting mouth parts, such as 

 grasshoppers and many beetles, eat vegetable food, in both 

 the larval and adult stages of their development. Others, 

 such as plant lice and cotton stainers, take plant food by 

 means of sucking mouth parts also during the whole of the 

 larval and adult life. Others, still, feed with biting mouth 

 parts in the larval stage, and in the adult one either do not 

 feed at all, or get their food by sucking the juices of plants 

 and flowers. "Many butterflies and moths :ar| examples of 

 these. Other examples of the variety of ways of feeding are 

 to be seen in the mosquito, the larva of which is a scavenger 

 or predator in stagnant water, while the adult male sucks 

 the juice of fruits and flowers, and the adult female the 

 blood of animals. Another example is to be found in many 

 bees and wasps, where the same individual possesses mouth 

 parts developed for both biting and sucking. 



The manner of feeding has a great influence on the 

 development of the food canal. Larvae, with biting mouth 

 parts, which feed on vegetable matter have very large ali- 

 mentary systems, while predaceous insects have smaller ones, 

 and those which suck the juices of flowers and plants, and 

 the blood of animals, smaller still. Certain insects which 

 suck their food, such as Lepidoptera, Diptera and Hemiptera, 

 have a development of the gullet which acts as a sucking- 

 pump, by means of which the food is taken up and forced 

 back into the stomach. In bees and ants, the region of the 

 gizzard is occupied by the honey-stomach, into which the 

 nectar can be taken and kept separate from the actual food 

 of the insect. The nectar or honey can be disgorged at will. 



Attached to, or communicating with, the alimentary 

 canal, there are two or three different kinds of glands, eacli 



