14 INVERTEBRATE ZOOLOGY 
Exercise 11. Remove carefully and with the aid of the dissecting 
microscope, if necessary, the antenne, labrum, mandibles, 
maxille, and labium of the beetle. Mount them on a 
slide and draw them on a large scale. Label carefully 
all the parts. 
Bxercise 12. The mouth-parts of the wasp are much more 
highly specialized than those of the beetle, as they are 
adapted not only for chewing, but also for licking. Remove 
the antenne and the mouth-parts of the wasp and mount 
them on a slide. The labrum and the mandibles will be 
seen to be similar to those already studied. The maxille 
and the labium, also, do not differ materially from those of 
the beetle or the grasshopper. The labium les between 
the two maxille, and its ligula is elongated and modified 
to form a licking organ. Draw an antenna and the mouth- 
parts on a scale of 6. 
Internal anatomy. Take the grasshopper in the hand and with 
a pair of fine, sharp scissors cut a slit through the body-wall a 
little to one side of the mid-dorsal line from one end of the 
body to the other, using great care not to injure the organs 
within. Place the animal, dorsal side up, in a shallow pan 
with a wax-covered bottom containing water or 80% alcohol. 
First, with two strong pins, pin the head to the wax and then 
the extreme hinder end of the body, then carefully spread the 
cut edges of the body-wall as widely as possible to the right 
and left and pin them down, using many pins on each side. 
Observe the organs as they lie in the body-cavity. In the 
thorax will be seen the strong locomotory muscles. Lying 
immediately beneath the dorsal abdominal wall in the median 
line is the heart; this may have been destroyed by the incision, 
but if not, it may be recognized as a narrow, transparent tube 
of the diameter of a needle, flanked by paired triangular muscles 
