14 Practical Zoology. 



pan; pin the hindermost ring of the abdomen firmly to the bottom 

 of the dissecting pan ; turn each hind leg outward and pin down. 

 With sharp, fine-pointed scissors, cut through each side of the 

 roof of the next to the last abdominal ring ; lift, with the forceps, 

 the cover of this ring ; continue to cut forward, on each side of 

 the abdomen, pulling the tergum upward and forward as it is 

 loosened. Thus carefully unroof the whole abdomen. 



2. The heart is a delicate tube, running along just under the 

 tergum, and probably was torn away with the tergum. 



3. On each side there is a row of air sacs, with their white air 

 tubes. 



4. In the anterior part of the abdomen a mass of yellow eggs 

 is usually to be found ; this mass may be easily separated into two 

 parts, right and left, from each of which a tube, the oviduct, leads 

 to an opening between the parts of the ovipositor. 



5. Under the eggs is the dark intestine, running lengthwise. 



6. Remove the roof of the thorax ; more air sacs should be 

 found here. In the upper part of the thorax are the white muscles 

 which move the wings. Removing these muscles exposes more 

 of the digestive tube ; as the food is swallowed, it passes upward 

 into a brown tube, which soon turns backward into the thorax ; in 

 the prothorax, the enlargement is the crop, in which is produced 

 the dark liquid which the grasshopper ejects from the mouth when 

 held captive. The crop may be removed, split open, washed, and 

 examined under the microscope with a half-inch objective to 

 show the rows of hooked teeth with which it is provided. A little 

 farther back the digestive tube is surrounded by a set of double 

 cone-shaped pouches, which extend parallel with the main chan- 

 nel of the digestive tube. These are the gastric ceca. Behind 

 them is the stomach, followed by the intestine. The products of 

 digestion pass through the coatings of the digestive tube, and 

 mingle with the currents of blood which pass along the ventral 

 and lateral parts of the body. 



7. The veins of the wings are air tubes, and are very different 

 from the veins in our bodies. 



