A GRASSHOPPER 13 
Exercise 8. With strong forceps remove the dark-colored mandi- 
bles and draw the inner surface of one of them on a scale 
of 5. 
Exercise 9. Remove the maxille, which lie just back of the 
mandibles, being careful to take out the entire structure. 
Mount them on a glass slide in glycerine or water with 
the posterior side uppermost, and examine them under the 
microscope. Note the following parts: the basal segment 
or cardo, by which the maxilla articulates with the head; 
the stipes, the broadest segment of the structure; the 
inner and the outer lobes, which project from the distal edge 
of the stipes; and the maxillary palp, which projects from 
the lateral edge of the stipes. Draw a maxilla on a scale 
of 5 and label all of these parts. 
Exercise 10. Note between the maxille and just in front of the 
labium a median projection, the hypopharynx. Remove 
the labium, taking care to leave none of it in the animal, 
mount it on a slide, and identify the following parts: 
the basal segment or submentum, by means of which the 
labium articulates with the head; the mentum, the succeed- 
ing segment; the ligula, which projects from the distal 
edge of the mentum; and the two labial palps, which project 
from the lateral edges of the mentum. The labium is a 
second pair of maxille fused in the median line. Trace 
the homologies between the parts of the labium and those 
of the maxille. Draw the labium on a scale of 5 and 
label its parts. 
The mouth-parts of the wasp and the beetle. The mouth-parts 
of the grasshopper are called biting mouth-parts because the 
insect bites or chews its food instead of licking or sucking it. 
Biting mouth-parts characterize all the more primitive insects. 
The mouth-parts of the beetle are similar to those of the grass- 
hopper, although the former is a much higher insect. 
