2 86 Handbook of Nature-Study 



if you can find the empty nymph skins from which the adults emerged. 

 Where is the opening in them? 



Observations on the adult dragon-flies— I. Catch a dragon-fly, place 

 it under a tumbler and see how it is fitted for life in the air. Which is the 

 widest part of its body? Note the size of the eyes compared with the 

 remainder of the head. Do they almost meet at the top of the head? 

 How far do they extend down the sides of the head? Why does the 

 dragon-fly need such large eyes? Why does a creature with such eyes 

 not^need long antennae? Can you see the dragon-fly's antennae? Look 

 with a lens at the little, swollen triangle between the place where the two 

 eyes join and the forehead; can you see the little, simple eyes? Can you 

 see the mouth-parts? 



2. Next to the head, which is the widest and strongest part of the 

 body? Why does the thorax need to be so big and strong? Study the 

 wings. How do the hind wings differ in shape from the front wings? 

 How is the thin membrane of the wings made strong? Are the wings 

 spotted or colored? If so, how? Can you see if the wings are folded 

 along the front edges? Does this give strength to the part of the wing 

 which cuts the air? Take a piece of writing paper and see how easily it 

 bends ; fold it two or three times like a fan and note how much stiff er it 

 is. Is it this principle which strengthens the dragon-fly's wings? Why 

 do these wings need to be strong? 



3 . Is the dragon-fly's abdomen as wide as the front part of the body ? 

 What help is it to the insect when flying to have such a long abdomen? 



Outline for field notes— Go to a pond or sluggish stream when the sun 

 is shining, preferably at midday, and note as far as possible the following 

 things : 



1. Do you see dragon-flies darting over the pond? Describe their 

 flight. They are hunting flies and mosquitoes and other insects on the 

 wing; note how they do it. If the sky becomes cloudy, can you see the 

 dragon-flies hunting? In looking over a pond where there are many 

 dragon-flies darting about, do the larger species fly higher than the 

 smaller ones? 



2. Note the way the dragon-flies hold their wings when they are 

 resting. Do they rest with their wings folded together over the abdomen 

 or are they extended out at an angle to the abdomen? Do you know how 

 this difference in attitude of resting determines one difference between the 

 damsel-flies and the dragon-flies? 



3. The damsel-flies are those which hold their wings folded above the 

 back when resting. Are these as large and strong-bodied as the dragon- 

 flies ? Are their bodies more brilliantly colored ? How does the shape of 

 the head and eyes differ from those of the dragon-flies? How many 

 different colored damsel-flies can you find? 



4. Do you see some dragon-flies dipping down in the water as they 

 fly? If so, they are laying their eggs. Note if you find others clinging to 

 reeds or other plants with the abdomen thrust below the surface of the 

 water. If so, these are inserting their eggs into the stem of the plant. 



Supplementary reading — Outdoor Studies, Needham, p. 54; "The 

 Dragon of Lagunita" in Insect Stories, Kellogg. 



