A MAGGOT TRAP IN PEACTIGAL USE. 7 



door and the second just inside the door, which faces the east. On 

 several occasions papers were exposed, but the counts are not given 

 in the diagram for the reason that a shower of rain or a strong wind 

 spoiled some of the papers. The numbers which are plotted are those 

 obtained on clear, warm days, on which the climatological conditions 

 were nearly the same except for the direction of the wind. This will 

 account for the irregular time intervals between the successive counts. 

 It is recognized that this method is not all that could be desired as 

 an accurate mdex of fly prevalence. The use of a small number of fly 

 papers in this way is nothmg more than a method of samphng, but 

 since the papers were exposed always in the same places and under 

 nearly the same climatological conditions, the method may be con- 

 sidered as rehable as any method of samphng used in other lines of 







"" 



T 



'" 





' 





~1 













-J:,... 











































■ 









^JCO [ 



'I r> 







/* 













\ ■ .__ 







2200 . . , . . ' ^ ; ■ ■ ' 1^ ! I\J 





^• 







^1 1 







'"'- ' ! i ' : ' s , / i 1 i 1 ^ 











T\\^ 







q"'''' / -'1 III 





1 











.'\"^ L__ __. __ 







j'^""' ' : ! 1 

















._:! 







\ """ ' ■'!■•'! ■ i 



















, - ' \ 





t'''^- , : ' , 1 ' 1 

















Iff . 



'' ^ 





*i '" ■ ' ■ ■ 1 1 









1 















\'';:- \- ■■■ :'Ml 

















_____ ^^ 





\ 



^7cc ' 



>, '■■'' 

















r viT 





', 



J „oo 



1 fOOO - - - - 

 5 900 - - — 













i 



r:::::|:::::: ::::::::::: 







-^^ 



■ ■ 1 ' ; ; 1 











1 



1 1 



/ 1 





\v- 



1 ■ : 1 











1 





t 





X 



•^ 



4 





1 







I 





\ 



1 \ 





\ 



'-J.| 







' 





___^ ^ 



\ T 





! «w-.l 



\ 





,, 





/ 





- i> 



41 I 





1, 



1 



"^ 







_,j_^,_____\ 



? T 



; 







'? 











« \ t^ t 



-iS S I'' 



1 





, 











S 











... _^______. __ 



"~\\f- ' 





T J 



1 





















^ ^ / 



t-— f---7 





J 



1 











? 











...,_____.__ _.,_.„. 



_,^__ 







1 











{ 













.;,__ __, .,. 





'^:::: 



J 







1 



6 











§ 





>, 



* % 



'c/t-y 



\ 



^ ^UGC/ST- 



— '^ ^£7^T£-/^S£^ ' 



J 



Fig. 3. — The broken line connects series of fly counts at the garbage pails near liitchen; the solid 

 line, those at the stable. (Original.) 



work. The use of a few fly papers in this way would not of itself 

 have any appreciable effect on fly prevalence. It was thought that 

 the use of fly traps would complicate the situation in that any appar- 

 ent reduction in the number of flies might be ascribed to their use 

 rather than to the maggot trap. 



A study of the fly counts shown in figure 3 reveals that there was a 

 decided drop in the mimber of flies both at the kitchen and stable very 

 shortly after the maggot trap was put into operation. Assuming that 

 all the flies at the stable and kitchen at the time the experiment began 

 (July 25) wen; freshly emerged and that tli(>y would all die off within 

 three week.s Ctliere is some evidence that IHes seldom hve longer than 

 this in midsummer), one would expect to find a reduction in the 

 ninnher of fhcs about August 10 or VI. As a matter of fact this is 

 wliat occurred. Altiioiigli the counts fluctuate considerably after 



