l6 NEW YORK STATE MUSEUM 



and several groups of larvae. The presence of these insects 

 is possibly explained by a small amount of light being ad- 

 mitted through a recent mousehole made from near station 6. 

 September ii there were a few small flies and dipterous larvae 

 together with two Glischrochilus quadriguttatus 

 Fabr. September 2^ Psycho da alternata was somewhat 

 numerous about the pail. 



The new pail placed in the house August 3 contained one or 

 two small flies the 23d. September 11 there were a few small 

 flies and several dipterous larvae from which a Drosophila was 

 subsequently reared. September 2,^ Psychoda alter- 

 nata was somewhat abundant. 



Summary. A careful scrutiny of the above records will show 

 that while Musca domestica and its larvae were found 

 .at both stations 23 and 6 there were none to be seen at stations 

 18 and 12. Furthermore, the house fly was much more abund- 

 ant in the pail just outside the house though the latter was in 

 a somewhat sunny place and owing to frequent rains and 

 rather low temperature, full of water practically all the time. 

 In this connection it is interesting to note that this pail with 

 its saturated contents was much more attractive than similar 

 pails within containing manure in a moist or rather wet condi- 

 tion. It may be worthy of note in passing, that the one place 

 w^here the writer found house flies literally swarming during 

 the past summer was in a barn cellar where hogs were run- 

 ning over thoroughly saturated excrement. There was a 

 marked difference in the number of small flies occurring in the 

 pail at station 18 as compared with the number found at sta- 

 tion 6 and it is probable that there would have been an almost 

 equally great dift'erence between the abundance of the dipter- 

 ous fauna at station 12, the darkest point of the house and 

 station 18, which at midday had an illumination which might 

 be characterized as twilight, had it not been for the mouse 

 burrows admitting light. 



The above data, w^hile not so conclusive as could be desired, 

 shows that the house or typhoid fly does not breed freely in 

 darkness. This pest exhibits a decided preference for sloppy 

 filth in light places. It is practical and thoroughly in accord 

 with the best agricultural practice to either draw out and 

 spread manure at frequent intervals, or to store it in cellars 

 or sheds. The relatively cheap cement underpinning makes 

 it comparatively easy to construct dark cellars, places where 



