The Honey Bee and the Fly 371 



doors. The maggots then cause intense pain as they feed on the sur- 

 rounding flesh. 



The stable fly (Stomoxys calcitrans) looks something like a housefly 

 except that it has a strong piercing beak and sucks blood from animals. 

 It is also supposed to be the insect which carries the germs of infantile 

 paralysis. 



The smaller horn fly (Haematobia serrata) swarms about the bases 

 of the horns of cattle, biting constantly. 



LIFE HISTORY 



Flies (Fig. 241) breed about filth and decaying matter though they 

 can and do breed in any wet fermenting vegetable or animal matter. 

 The maggots are hard to kill ; they will live in pure kerosene for over 

 an hour and even more than thirty minutes in alcohol. They have 

 even been bred from the open boxes of snuff on a druggist's counter, 

 though tobacco is supposed to be quite injurious to insects. 



After the housefly's eggs are laid, it takes about eight hours for thern 

 to hatch into* maggots. These finish their growth in six to seven days, 

 burrowing into the ground "under the manure pile" (hence the need of 

 concrete floors) and transform into brown puparia, from which they 

 emerge as adult flies in three days. 



Hodge and Dawson have summed up the rapid increase in flies most 

 tellingly in the following words : "After coming out as adults, they fly 

 about over an area not generally more than one thousand yards in 

 diameter, and feed and drink from two hundred to three hundred times 

 a day for from ten to fourteen days before maturing their first batch of 

 eggs. This actually delivers the enemy into our hands. It means that, 

 with flytraps on every garbage can and swill barrel, and with everything 

 most attractive to flies very carefully kept in these receptacles, not a 

 single fly will succeed in feeding for two weeks without getting caught. 

 In this case no more eggs will be laid, and the pests will vanish. 



"Allowing ten days of feeding between emergence and oviposition, 

 figuring that a fly lays 150 eggs at a batch and lives to lay six batches, 

 compute the increase of a pair of flies beginning to lay May 1. Half 

 the progeny are supposed to be females. Test the following figures : 



May 10 . . 152 flies. 



May 20 302 flies. 



May 30 11,702 flies. 



June 10 34,302 flies. 



June 20 911,952 flies. 



June 30 6,484,700 flies. 



July 10 72,280,800 flies. 



July 20 325,633,300 flies. 



July 30 5,746,670,500 flies. 



