INSECTS 1 



4. (Optional demonstration or home work.) Place a tiny 



drop of honey or molasses diluted with water near 

 a butterfly. If the insect does not seem to realize 

 the presence of the sweet substance, touch the pro- 

 boscis with the needle, or if necessary put the needle 

 into the coil of the proboscis, and gently unroll it. 



a. Describe what you have done to get the animal to eat. 



b. Describe the movements of the proboscis. 



c. What reason do you find for supposing that the butter- 



fly is feeding? 



d. What reason have you for thinking that the proboscis 



.must be hollow? 



5. (Optional.) Between the two antennae, and projecting 



upward in the anterior region of the head, are two slen- 

 der structures covered with hair ; they are the labial 

 palps. In some butterflies the labial palps are incon- 

 spicuous. If they show in your specimen, describe 

 them as to their position and appearance. 



C. Organs of the thorax; locomotion. 



1. How many pairs of wings has the butterfly? 



2. Describe a wing as to comparative length, breadth, 



and thickness. 



3. Hold a butterfly between your eyes and the light, 



and study carefully the course of the veins in the two 

 wings on one side. Toward what region of the wings 

 (i.e. proximal or distal) do the main veins converge ? 



4. Bend the veins and the connecting membrane in a 



wing that is given you. 



a. Which is the more rigid? 



b. What, then, is one use of the veins? 



5. Take a small piece of the wing of a butterfly that is 



given you and rub the surface with your finger tip. 

 a. Describe what you have done, and state how the 

 substance on your finger compares in color with 

 the color of the part of the wing before it was 

 rubbed. 



