Proceedings of Eighth Annual Meeting 8i 



sequent changes in untrained personnel. These factors do not apply 

 to the collections for 1920, and it is true that the increased totals for 

 that year are due in part to the facts that all of the collections were 

 made from the same group of representative houses, that these 

 houses were collected regularly and that the work was done by the 

 same personnel under careful checking throughout the season. 

 From this it is seen that subsequent data may show the final aver- 

 ages obtained to be nearly normal, at least much nearer the normal 

 than any low year available would indicate, 



A few of the highest collection records made during the work 

 are of interest to show what has been encountered on this plant- 

 ation in the way of maximum abundance. Four hundred and thirty- 

 five Anopheles were collected inside a four room house occupied by 

 a tenant family of eight people in 191 5, 754 Anopheles weie taken 

 from a single table in September, 1919, and 4968 were found under 

 one house in June, 1920. In the last record not all of the mosquitoes 

 were collected, the remainder being counted after more than 3800 

 had been actually collected in the chloroform tubes. In 1920 this 

 same house had an average of over 2000 Anopheles for each collect- 

 ion of the five summer months (collections made once a month). 

 The June averages for all of the 25 houses which were collected 

 underneath in 1920 was 1040 Anopheles per collection per house 

 and these houses were all scattered over plantation with a maximum 

 distance between the two farthest removed from each other of about 

 three miles. 



The tenant houses and their out-buildings are apparently the 

 principal resting places for the engorged female Anopheles, and the 

 majority of the specimens which have fed at night on the people or 

 on the domestic animals around the place can probably be taken 

 the following day from these resting places. An idea of the amount of 

 feeding which takes place may, therefore, be obtained' from the 

 above data. The average of 310 female Anopheles is taken as the 

 daily rate for each tenant house and its out-buildings. The per- 

 centage of fed females as indicated from the dissection of over 2085 

 Anopheles collected at Mound in 1917 was 84%. This applied to 

 the rate of 310 reduces that figure to 260.4 fed females about each 

 place. The average number of people in the tenant families on 

 this plantation was 4.26 for the years, 1915,1916 and"i9i7. A 

 count of the domestic animals at 24 places in 1920 gave totals of 53 

 mules and horses, 32 cows and calves, 172 hogs and 26 dogs, or an 

 ^ average of 11.79 which when added to the number of people makes 



