KOR.M AND FUNCTION 



271 



of small scissors open the specimen on the median line 

 of the back, the full length of the body. Be careful 

 not to cnt deeper than the body-wall, lest the internal 

 organs be disturbed ; pin down the sides of the body 

 to the cork. The specimen is now ready for study 

 npon the dissecting-stand. 



The specimen can be more readily manipulated if 

 the block or cork of wood holding it be placed in a 

 vessel containing just enough water to cover the speci- 

 men. The internal organs will float out and stand 

 up more distinctly. 



FIG. 209. Digestive, circulatory and nervous systems of female grasshopper. 1, 2, 3, 4, 6, 6, 

 7, 8, 9, 10, 11, 12, segments; a-a, digestive tract; H, hypopharynx ; Lb, labium; Lm, labrurn ; 

 Lp, labial palpus ; mp, maxillary palpus ; (J?, tesophagus ; 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. 



The digestive system begins with the masticatory 

 organs of the mouth, previously shown. (Figs. 193, 

 195.) The food is here masticated and mingled with 

 the saliva secreted by glands lying under the esopha- 

 gus. From the esophagus it passes into the crop, 

 where it is retained until mixed with the saliva. 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 



