144 



ENTOMOLOGICAL NEWS. 



[April, 'iS 



males, and the latter only females. It is interesting to note 

 this high percentage of females even in species that do not 

 breed in excrement. Miisca domestica females were about 

 three times as numerous as males, 564 to 197. The same re- 

 lationship was found to hold good when flies were trapped 

 out-of-doors with human excrement for bait, females being 

 in that instance about four times as numerous as males. 1 

 have no data to show the comparative abundance of the two 

 sexes in houses, but it is apparent that as a seeker of filth the 

 female house fly is potentially more dangerous to the human 

 species than the male. For this reason any bait that will at- 

 tract more females than males should be considered more ef- 

 ficient than one which will attract an equal number of both 

 sexes. Several baits were tried with this in view and a com- 

 bination of beer and oatmeal was found the most effective. 



Table Giving Data Concerning Flies Captured in Privy Trap Expkri.mk.nt 

 AT Laurel, Montana, July 20 to August 21, 1914. 



Hodge Traps 



Males Females Total 



Miisca domestica ... 

 Muscina stabulans . 



M. assimilis 



Lucilia sericata .... 



L. caesar 



L. sylvarum 



Phorm ia regina . . .. 

 P. terraenovae 



Calliphora erythrocephala "J 



C. color aden sis > 



C. latifrons ) 



Slomoxys calcitrans 



Fannia scalaris "j 



F. caniciilaris > 



F. sp J 



Ophyra leucostoma 



Myospila rnetabunda 



Ravinia peniculata. . 



Sarcophaga haemorrhoidalis.. 



S. cooler i 



Anacampta latiusciila 



Eristalis tenax 



Syritta pipiens 



Culex tarsalis 



Culiseta inornaius 



Undetermined Tachinidae 



Totals 



'97 



274 



1609 



564 



1078 



I 



678 



120 



I 



46 



2949 



761 



1352 



I 



679 



120 



I 



63 



4558 

 378 



6 



33 

 4 

 5 



82 



137 



9 



8330 



Trap 

 Clean- 

 ings 



113 

 222 



509 



Species 

 Total 



1346 



874 

 1574 



"45 



64 



2 



'•56 



I 



5067 



378 

 10 

 I 



47 



4 



39 



166 



'37 



9 



I 



9676 



Species 



Per 



Cent 



OF Total 



Catch 



9-03 

 16.27 



11.83 



.66 

 .02 



52.37 



•49 



.04 

 .40 

 1.72 

 1.42 

 .09 

 .01 



