174 THE BIOLOGY OF THE ANIMAL 



find the average size. Plow many colors do you 

 find on the body ? How are they distributed ? 



h. The head. — What is its shape as seen from the front ? 

 From the side? From above? How is it con- 

 nected to the thorax? Is there a movable neck? 

 How many pairs of appendages does it bear ? 

 On the head find 



1. The compound eyes. — How many? How sit- 



uated? Are they upon eye-stalks ? Compare 

 with crayfish. What is their color ? Shape ? 

 Size ? Examine with a hand-lens. Estimate 

 the number of facets in the eye. What is the 

 shape of the facets ? Examine the compound 

 eye as an opaque object, under the low power. 



2. The ocelli or simple eyes. — How many? How 



situated ? Color ? Shape ? Size ? Compare in 

 all respects with the compound eyes. 



3. The antennae. — ISTumber? Position? Struct- 



ure ? Color ? Shape ? Size ? Compare with 

 crayfish. How do you account for the differ- 

 ence in the length of the antenna of the two 

 .animals ? Examine with a hand-lens and count 

 the joints. Examine several specimens to see 

 if the number is constant. Are there any varia- 

 tions in the size of the joints ? Are the anten- 

 nse true appendages ? Why ? Are the anten- 

 nae of the locust homologous with those of the 

 lobster ? 



4. Cephalic plates. 



Make out the following plates composing the 

 head : 

 The top and front of the head are formed by 

 {a) The epicranium. — What is its shape ? What 



