INSECTA 91 



for a minute, and then settle down again. The "flapping" 

 is to notify females that an amorous male is abroad. It 

 displays the yellow and black of the under wings and the 

 sound produced has a certain pitch which is characteristic 

 for each species in the family to which the Carolina locust 

 belongs. If there is an unfertilized female near, she comes 

 to the male and he pokes a little packet 'of sperm into 

 her seminal receptacle with his cerci. She is now pre- 

 pared to lay fertile eggs. The red-legged locust does not 

 make such a splendid display as its larger relative, just 

 described. However, it sits in the grass and sings a feeble 

 song which is easily recognized by females of its own 

 species. 



The bright " recognition " colors, the sound-producing 

 organs, and ears, are of little or no value in procuring food 

 or for self-protection, but are adaptations for mating! So 

 grasshoppers use many means to insure fertile eggs, and the 

 continuance of the race. 



After a female grasshopper has been " fertilized" the 

 sperm cells move to the eggs and enter them, the egg and 

 sperm nuclei fusing in the cytoplasm of the egg cell. Thus 

 a single cell is formed by the union of the egg and sperm 

 cells. This new cell is the zygote. It has all the character- 

 istics of youth, as described in Chapter III, and is the 

 beginning of a new individual. 



Soon after the zygote has been formed it begins to seg- 

 ment, or undergo mitotic cell division (Fig. 25). First the 

 nucleus divides several times and the new nuclei arrange 

 themselves near the outside of the egg ; the cytoplasm about 

 each nucleus becomes separate from the rest and a number 

 of little cells are thus formed just beneath the egg-shell 

 (Fig. 44, A, B, C). Development takes place on the out- 

 side of the egg because the yolk, or food material fills the 

 interior. As the cells continue to multiply a little embryo 

 is soon formed on one side of the "egg" (D), and this later 

 is enveloped by two protective membranes which are known 

 as the amnion and serosa (E, F). Finally the yolk is all 



