MOSQUITOS. 359 



W. H. Hudson ("Naturalist in La Plata") 

 states that Mosquitos vanish as if by magic when a 

 dragon-fly appears. It has therefore been suggested 

 that one or two dried dragon-flies suspended from 

 fine silk, under the roof of an open porch infested 

 with Mosquitos, will scare all the little pests away, 

 and they will not come back while the dragon-flies 

 are there. 



Scientific investigators have discovered that Mos- 

 quito larvae cannot endure paraffin oil. One drachm 

 poured on the surface of a pool about a square yard 

 in area is sufficient to destroy all the larvae. As they 

 keep to the surface, I suppose that the depth of the 

 water does not matter. 



I propose next to describe a method which is of 

 my own invention. It is known that a water plant 

 called Utricularia devours not only small insects, but 

 even very minute fish just hatched. The plant is 

 covered with little bags or open bladders ; if an insect 

 or a fish puts his head into one of these bags, he is 

 lost. Now, the lame of gnats, if I do not mistake, 

 are captured among other small fry by the Utricularia. 

 Then, why not supply each tank, pond, cistern, and 

 reservoir with a plant of Bladderwort ? You might 

 put in a carp as well ; then if the Mosquito did not 

 come to grief by peeping into a bladder, the carp 

 would be sure to do for him. 



The Chinese plait a kind of " creeping jenny " 

 into a rope, which they light at the lower extremity 

 and hang near the bed. This, it appears, smoulders 

 slowly, emitting a pungent, aromatic, not wholly un- 

 pleasant odour, very unacceptable to the Mosquitos, 

 which keep at respectful distance. 



