THE GRASSHOPPER. 



THE following outline will apply to any of the common 

 grasshoppers, though the larger ones are, of course, pref- 

 erable for the study of the structure. 



I. External Anatomy. 



1. General Characters. The body of the grasshopper is 

 made up of head, thorax and abdomen. Are these divisions 

 well marked ? Are they as well differentiated as in the crayfish 

 and earthworm? Are somites present ? Are they found in all 

 regions of the body? Is an exoskeleton present? Compare 

 with the crayfish in regard to exoskeleton. In what ways 

 do they differ? Are appendages present? Are they found 

 in all regions of the body? 



2. The Head. What is its shape? How is it attached 

 to the thorax? Study the position and structure of the 

 antennae. Observe the large compound eyes. With a lens 

 determine why these are called compound eyes. In addition 

 to these eyes there are three simple eyes or ocelli. One in 

 the center of the head, below the antenna?, and the others 

 near the dorsal, anterior border of the compound eyes. 



About the mouth are several appendages: (a) labrum, 

 or upper lip; (6) mandibles, or jaws; (c) maxillae; (rf) 

 labium or lower lip. Observe the position each occupies 

 and the direction of movement. Remove the appendages, 

 note the structure of each one and make a drawing showing 

 this structure. 



