26 FIELD ZOOLOGY. 



two extensions of the canal between the oesophagus and 

 the stomach. (Fig. 13.) 



In the human being the food is mixed with the saliva 

 while it is in the mouth ; in the bird, the food is swallowed 

 dry or whole, and this mixing with the saliva is accom- 

 plished in the crop. Peptonization is accomplished for 

 birds and for many insects by a second enlargement, 

 which has already been spoken of, just below the crop. 

 In insects, the salivary glands may be restricted to the 

 head and the saliva be discharged from there into the 

 mouth; or the glands may extend backward into the 

 thorax. In connection with the salivary glands, there 

 may be poison glands in such insects as are predatory 

 or carnivorous, and also in spiders. 



In the honey bee and the honey ant, also, this crop 

 or . fore-stomach serves as a temporary storage cavity for 

 the liquid foods which have been eaten by the bee or the 

 ant, or brought to the nest bee or ant by some foraging 

 bee or ant. The cavity is separated from the true stomach 

 by extruding flaps or outfoldings of its walls into the 

 cavity of the true stomach; and the food swallowed is 

 thus kept indefinitely or let out either forward or back- 

 ward by the voluntary effort of the insect. Such insects, 

 like some birds, feed their young by regurgitation. Such 

 preparation of the food as part of the alimentation of the 

 parent is evidence of their high position in the scale of 

 life, and of their close relationship to the mammals, the 

 highest of the animal kingdom. 



In carnivorous insects this crop is a dilation of the 

 canal axis; but in the Neuroptera and the butter- 

 flies, bees, wasps, ants, and the flies, this salivary 

 extension of the canal is a lateral pocket, and serves 

 in all of them for the temporary storage of food just 



