334 ZOOLOGY. 



bunch of follicles, emiitying by a common duct into the floor 

 of the mouth. 



The (Esophagus is succeeded by the crop [inghivies). It 

 dilates rapidly in the head, and again enlarges before pass- 

 ing out of the head, and at the point of first expansion or 

 enlargement there begins a circular or oblique series of folds, 

 armed with a single or two alternating rows of simple spine- 

 like teeth. Just after the crop leaves the head, the rugae or 

 folds become longitudinal, the teeth arranged in rows, each 

 row formed of groups of from three to six teeth, which 

 point backward so as to push the food into the stomach. 

 In alcoholic specimens the folds of the crop and oesophagus 

 are deep blood-red, while the muscular portion is flesh-col- 

 ored. It is in the crojD that the " molasses " thrown out by 

 the locust originates. 



The proventrictdus is very small in the locust, easily over- 

 looked in dissection, while in the green grasshoppers it is 

 large and armed with sharp teeth. A transverse section of 

 the cro}) of the cricket shows that there are six large irreg- 

 ular teeth armed with spines and hairs (Fig. 282). It 

 forms a neck or constriction between the crop and true 

 stomach. It may be studied by laying the alimentary canal 

 open with a pair of fine scissors, and is then seen to be 

 armed with six flat folds, suddenly terminating j)osteriorly, 

 where the true stomach (chyle-stomach, ventriculus) begins. 

 The chyle-stomach is about one half as thick as the crop, 

 when the latter is distended with food, and is of nearly the 

 same diameter throughout, being much paler than the red- 

 dish crop, and of a flesh-color. 



From the anterior end arise six large gastric cmca, which 

 are dilatations of the true chyle-stomach, and probably serve 

 to present a larger surface from which the chyle may escape 

 into the body-cavity and mix with the blood, there being in 

 insects no lacteal vessels or lymphatic system. 



The stomach ends at the posterior edge of the fourth ab- 

 dominal segment in a slight constriction, at which point 

 (pyloric end) the urinary tubes {vasa urinaria, Fig. 281, 

 Mr) arise. These are arranged in ten groups of about fifteen 

 tubes, so that there are about one hundred and fifty long, 

 fine tubes in all. 



