72 LIFE-HISTORY STUDIES 



out the old water and adding fresh, using water from the original 

 source if possible. 



E. Observe the feeding and breathing habits of the wrigglers. 



F. Take several of the wrigglers from the jar and place them 

 in another jar of water. Then add a few drops of kerosene. 

 Note the behavior of the insects. 



G. Observe the dates when the wrigglers cast their skins 

 (moult). 



H. After a given number of days the pupal (tumbler) stage is 

 reached. Observe breathing methods. 



I. If you wish to save the mosquitoes you must now cover the 

 jars with a screen, or preferably a glass funnel, which can be 

 plugged up, and permits one to capture the mosquitoes more 

 readily. 



J. Transfer the mosquitoes to a breeding cage provided with 

 a dish of water. After allowing the female mosquitoes to have 

 a suck of blood, note the date of egg deposition. 



EXERCISE 41 



LIFE HISTORY OF A FLEA 



, 



A. Collect specimens of fleas from a dog and place the fleas in 

 a glass vial covered with gauze. The females usually deposit 

 eggs very readily. 



B. After several days the flea larvae will emerge. You must 

 now add some moist sawdust and fecal material from rodents, 

 or dry blood. The vials must be kept in a warm place, other- 

 wise growth is exceedingly slow. 



C. If possible follow the growth of the flea larva to the time 

 when it spins a cocoon and pupates. 



D. Pupae can be kept under observation more readily. Note 

 the date when the flea emerges. 



