THE COMMON RED-LEGGED GRASSHOPPER 7 



continues as a slightly coiled tube, the intestine, and ends 

 posteriorly at the anal opening (Fig. 3). 



The functions of these different parts are as follows. The 

 food, after being crushed by the mandibles and moistened by 

 the saliva, enters the crop, where it is subjected to the action 

 not only of the saliva but also of a fluid from the gastric 

 caeca. The "molasses" thrown out from the mouth as a de- 

 fensive fluid by the grasshopper, when handled, consists of 

 partially digested food from the crop, mixed with the diges- 

 tive fluids. When sufficiently dissolved and changed chemi- 

 cally, the food filters through the spines of the gizzard into 

 the stomach, where it is further acted upon by another 

 digestive fluid. The thin walls of the stomach allow the 

 prepared food to pass through and mingle with the blood 

 in the general body cavity. This process is called absorp- 

 tion. The anterior part of the intestine is thin-walled, and 

 absorption may take place there and also in the caeca. The 

 unused food material passes from the body by way of the 

 anal opening. 



The Circulatory System. When the food has been acted 

 upon by the various digestive fluids, and so changed that it 

 may be used to supply the different organs with nourish- 

 ment, it is distributed over the body by the circulatory sys- 

 tem. At the same time certain waste matters are taken 

 away and carried to organs which remove them from the 

 body. In the case of man and many other animals, the cir- 

 culatory system is also the means by which oxygen is carried 

 to all the organs; but, as we shall see in a moment, this 

 work is otherwise provided for in the grasshopper. As soon 

 as the prepared food has been absorbed by the walls of the 

 stomach and intestine it mingles with the blood, which flows 

 through the body cavity in sinuses (spaces between the 

 various organs), though not in definite blood vessels. The 

 blood is propelled by a tubular, pulsating vessel, or heart 



