99 



Experiments a little later gave the 



in less than twenty-four hours, 

 following periods: 

 Ang. 21. Eggs deposited in confiuement placed at 7 p. ni. ou cow duug free from 

 eggs of other Hies. 



23. Larvie one-fonrth grown. 

 25. LarviB oue-lialf inch loug. 



27. Larv.'c leaving niannre and entering sand to pnpate. 

 Sept. 5. Three flies issued. 



Aug. 23. Eggs placed with isolated duug at 1.30 p.m. 



24. (9». m.) Eggs liave hatched. 



25. Larvte oue-fourtli inch long. 



29. Apparently full grown. 



30. Puparia found. 

 Sept. 5. Two flies issued. 



6. Four flies issued. 



1. Eggs deposited 10.2.') a ni. 



2. Eggs were hatched when examined at 9 a. m. 

 5. Larviii half grown. 



7. LarvtB entering sand. 



8. Five puparia taken from sand. 



9. All in puparia. 



15. Three adults. \ 



1(5. Twenty adults. > All found at 9 a. m. 



17. Twenty-six adults. ' 



17. Twenty adults, issued between 12 and 4 p. m. 



From these records it will be seen that from ten to seventeen days, 

 say two weeks, is about the average time from the laying of the egg to 

 the appearance of the flies, and with four active breeding mouths, from 

 May 15 to September 15, there will be eight generations. The flies will 

 undoubtedlj" breed later thau September 15, but we may allow this time 

 to make up for the time occupied in the development of the eggs in the 

 abdomen of the female. With seven or eight annual generations the 

 numbers of the flies are not surprising. 



Fig. 13.— H^MATOBiA SEKUATA: «, head of female, front view; b, Lead of male, front view ; c, head 

 from side— all enlarged. (Original.) 



The adult — Its Habits. — The flies were observed in the greatest 

 abundance duriug July. They make their first noticeable api)earance 



