INSECTS 



67 



Fig. jii. — .4, Row of 



Spines, z, used in 

 chirping. 



B, the same more enlarged 



largest joint of the hind leg for a row of small spines visi- 

 ble with the aid of a hand lens (Fig. m). The sound is 

 produced by the outer wings rubbing against the spines. 

 Have you noticed whether the sound is 

 produced while the insect is still or in 

 motion ? Why ? The male grasshop- 

 pers of some species, instead of having 

 spines, rub the under side of the front 

 wing on the upper side of the hind wing. 

 Wings. — To what is the first pair 

 of wings attached ? The second pair ? 

 Why are the wings not attached to the 

 prothorax ? Why are the wings attached 

 so near the dorsal line of the body ? Why are the second 

 and third rings of the thorax more solidly joined than the 

 first and second rings ? 



Compare the first and second pairs of wings in shape, 

 size, colour, thickness and use (Fig. 112). How are the 



second wings folded so as to go 

 under the first wings ? About 

 how many folds in each ? 

 Draw a hind wing opened out. 

 Head. What is the shape of 

 the head viewed from the front, the 

 side, and above ? Make sketches. 

 What can you say of the neck? Is 

 the head movable in all directions ? 

 What is the position of the large 

 eyes ? Like the eyes of the cray - 

 fish, they are compound, with many facets. But the grass- 

 hopper has also three simple eyes, situated one in the middle 

 of the forehead and one just above each antenna. They 

 are too small to be seen without a hand lens. How does 



Fig. 112. — Grasshopper in 

 Flight. 



