92 DRAGON FLIES VS. MOSQUITOES. 



produce a realization of the expectations raised by the 

 circular, it would not be proper to conclude this paper 

 without suggesting methods of destroying or limiting the 

 number of flies and mosquitoes. 



At the outset the principle is enunciated that in order 

 to compass the destruction of any insect it is only neces- 

 sary to interrupt or break the chain of conditions which 

 are inseparably connected with its life history. It fol- 

 lows, then, that we may absolutely destroy any insect by 

 removing every particle of the material Nvhich serves it for 

 food or as a home during its larval period. If there be 

 wanting such material or home, no egg will be laid, no 

 larva will hatch, and no pestering imago will be perfected. 

 The powders, washes, and mixtures wliich the housewife 

 and the farmer are constantly wasting time and money in 

 distributing and applying, only bring other annoyances. 

 The bed bug will leave a house in one season if, after the 

 beds and clothing are thoroughly cleaned of nits and ma- 

 ture individuals, the posts are isolated by being placed on 

 bricks set in vessels of w^ater ; the potato beetle in the 

 State would disappear for a considerable period if the 

 farmers should unanimouslv omit to plant that vegetable 

 for one season ; the phylloxera w^ould instantly perish if 

 the vines were totally cut down and burned. Millions of 

 dollars could be expended in apparatus fo: the breeding of 

 dragon flies, while the filthy little duck pond or marsh, 

 which a few dollars would fill up, and costing nothing but 

 indifference to maintain, would supply mosquitoes enough 

 to satisfy the voracious appetite of all the dragon flies 

 that such apparatus could produce. 



How shall houses, cities, and neighborhoods, then, be 

 freed from the house fly and his congeners ? I answer : 



I 



