354 THE LOCUST 



tongue-like hypopharynx. It is, however, entirely outside the 

 digestive tract, and the true mouth is the opening just anterior to 

 the hypopharynx. Opening into this buccal cavity on the 

 anterior face of the labium, and just posterior to the hypopharynx, 

 is the salivary dud, which leads from the salivary glands located 

 in the thorax. The mouth, which is surrounded by a mem- 

 branous peristome, leads into the esophagus, which passes dorsally 

 as a narrow tube and enlarges into the thin-walled crop which 

 extends posteriorly in the thorax almost at right angles to the 

 esophagus. The crop tapers posteriorly, and where it leads 

 into the proventriculus, which is the next division of the tract, 

 there are six slender outgrowths, the gastric cmca, extending 

 anteriorly and posteriorly from their points of attachment. 

 The gastric caeca secrete a digestive fluid resembling the pan- 

 creatic secretion of a vertebrate animal. Posterior to the pro- 

 ventriculus is a division of the tract known as the ventriculus, 

 which is the true stomach of the insect. The beginning of the 

 intestine is not sharply separated from the ventriculus, but the 

 place is indicated by the Malpighian tubules which arise in a 

 circle at the anterior end of the intestine. These tubules are 

 supposedly excretory in function. Posteriorly, the intestine is 

 continued as the terminal portion of the tract, which is the 

 rectum. 



The animal bites off pieces of the grass or other vegetation 

 with its mandibles, using the labrum and labium as upper and 

 lower lips, respectively, and the maxillary and labial palps as 

 tactile organs. A salivary secretion which is emptied into the 

 cavity enclosed by the mouth parts serves as a lubricant in the 

 swallowing of the foo^ and perhaps as a digestive fluid after the 

 food has reached the crop. As the name implies, the crop func- 

 tions principally as a storage region. Some digestive changes may 

 occur in its posterior end, but the proventriculus and ventriculus 

 are the principal regions of digestion. The " molasses " that is 

 extruded from the mouth when a living grasshopper is handled is 

 the contents of these anterior portions of the digestive tract min- 

 gled with the digestive fluid of the gastric caeca. Absorption in 

 this instance would be defined as the passage of the diffusible 

 products of digestion, through the walls of the digestive tract, into 

 the blood contained in the haemoccele which surrounds the diges- 

 tive organs. 



