THE COMMON HOUSE-FLY. 149 



will appear later. As soon as the nights become cool, flies 

 try their very best to find shelters for the winter, and no 

 matter how carefully we may protect doors and Avindows 

 with screens they will find an entrance, to the great worry 

 of our better halves. Sufficient numbers would thus find a 

 shelter and survive the rigors of a northern winter, if they 

 did not bring with them at the same time an enemy they can 

 not escape, and one that will kill the very great majority of 

 all house-flies at that season. Only a few escape this 

 "slaughter of the innocents," and these few^are the ones that 

 may be seen during the w^inter in our houses; others will 

 find wintering quarters under rubbish, and remain in a 

 torpid condition until the warm weather of spring coaxes 

 them back to life. Most flies that escape death in autumn 

 hibernate in their winged form; a few may also winter over 

 as pupae, though this is doubtful, at least in Minnesota. 



"Have you ever observed a genuine house-fly, one with a 

 full pedigree? This question seems absurd, but the writer's ex- 

 perience has been that really few persons can tell the difference 

 between a house-ffy and other flies so common in our houses. 

 All flies found upon our walls, upon windows and tables, 

 are called house-flies, yet at least a dozen species are mixed 

 up in that congregation, all widely different, more so than 

 cows and horses. One of the most curious habits of the 

 genuine Simon-pure house-fly is its peculiar position during 

 sleep, and once observed it will always be recollected. When 

 we enter a dark room all flies are sleeping, but only the 

 house-flies sleep with their heads downwards, the others in 

 a more normal position. By bringing a light into the room, 

 you may ascertain very rapidly the proportion of true 

 house-flies to that of other intruders. Notwithstanding our 

 intimacy with the fly, or rather its intimacy with us, how- 

 very little is really known of it by the plurality of tormented 

 humanity! Those present always excepted, not ten per cent 

 of our fellow citizens ever know how many legs or wings a 

 fly has or where it spends its early days in infantile sports. 

 How many know why it so suddenly appears in countless 

 numbers to torment the masterpiece of creation, not caring 

 a straw when or where it attacks him? The ministers in 



