THE FLY 183 



Neither did Pharaoh know that the dirt on one of 

 the hairs of a fly's leg could by its simply walking 

 over his food leave bacteria enough to pollute it and 

 spread disease throughout his entire land. 



These conditions so well expressed in the few lines 

 of Pharaoh may well be duplicated in any uncleanly 

 city or army encampment, or engagement where dis- 

 ease kills more than bullets. 



The fly's eggs are deposited very quickly as many 

 as 120 in a mass, and it would be mostly luck if a 

 picture close enough to show were made of it. The 

 eggs are about twice as long as their diameter, shin- 

 ing white. They hatch in eight to twelve hours, de- 

 pending on the temperature. 



I found that 8 P.M. was the most likely hour to 

 watch for this pestiferous event. The actual period 

 of hatching took only five to fifteen seconds from the 

 time the egg split till the almost transparent maggot 

 wiggled out of his digestive tract. A black line was 

 clearly seen, as he quickly crawled away to start five 

 or six days of constant eating and growing. By that 

 time they are half an inch long. Then they become 

 sluggish and for two or three days they wander 

 around looking for a place to rest during the pupa 

 stage. When the actual time comes they simply go to 

 sleep. The head contracts into the body and they 

 become what looks like the egg from which they 



