GRASSHOPPERS IN GENERAL. 



45 



glands lying under the esophagus. From the esophagus it passes 

 into the crop. The food then enters the gizzard-like proventriculus ; 

 the inner walls of this are lined with chitinized processes which, by a 

 series of contractions, grind up the food and pass it on into the 

 stomach proper. Lying alongside of this 

 stomach, and connected to it, can be seen on 

 each side three long tubes. These are called 

 gastric pouches (ceca), because it is believed 

 that they secrete a fluid which corresponds to 

 the gastric juice, and this fluid enters the 

 stomach to perform functions similar to that 

 carried on by the gastric juice. 



The food after leaving the stomach passes 

 into the intestines, the upper part of which is 

 called the ileum and the lower part the colon. 

 At the forward end of the ileum can be seen a 

 large number of tubes (malphigian tubes) run- 

 ning backward. These are believed to perform the same functions as 

 the kidneys do in the higher animals. While the food is in the 

 stomach, and as it passes through the ileum and colon, it is believed 

 that .the nutritive portions oozing through the walls of this digestive 

 tube enter the circulation. The waste material is carried off through 

 the colon. 



Circulatory system. In this locust there are no arteries and no 

 veins. The circulatory system, as far as organs are concerned, is com- 

 prised of what we are wont to call the heart. This organ is a tube 



FIG. 24. (Original.) Ex- 

 terior view of auditory or- 

 gan ; Sp, spiracle. Enlarged 

 about fifteen times. 



FIG. 25. (Original). Digestive, circulatory and nervous systems. 1, 2, 3, , 5, 6, 7, 8, 

 9, 10, n, n, segments ; a-a, digestive tract; //, hypopharynx ; Lb, labium ; Lm, labrum ; 

 Lp, labial palpus ; mp, maxillary palpus ; (E, esophagus ; pp, ovipositors ; eg, egg guide ; 

 co, colon ; r, rectum. The heart is an open tube running along the back ; it is so marked, 

 but not easily shown. Enlarged three times. 



extending from about the tenth segment of the abdomen up into the 

 head. This tube has valves along its sides which admit of entrance 

 of food and do not allow that which has entered to escape until it 

 passes out of the main opening at the end of this organ in the head. 

 This leads us to make a few remarks concerning the blood of insects. 



