3I0SQU1T0ES IN GENERAL 31 



four mosquitoes, and on looking- around for their breeding- 

 place lie discovered it in a tank at tlie corner of the 

 greenhouse, in which the gardener was in the habit of 

 keeping- from thirty to forty gallons of cistern water, in 

 order that it might be of the temperature of the g-reen- 

 house. The tank Avas apparently full of mosquito larvae. 

 On measuring out in a quart jar, and counting them, Mr. 

 Matheson estimated that there were probably in the neigh- 

 borhood of three thousand larvae. This is a very inter- 

 esting instance as illustrating the point upon which we 

 have just insisted, since, after the exterminating work 

 which had been done, these three thousand mosquitoes 

 would have caused considerable annoyance to the house- 

 hold, and might have given rise to the opinion that they 

 had flown in from an unknown distance. 



Mr. H. C. Weeks, in the Scientific American Siq^pleinent 

 for January, 1900, very forcibly jiuts one aspect of mos- 

 quito breeding in the following words : "... a care- 

 ful supervision by those whose study of the subject 

 quickly enables them to detect the dangers from old 

 sources, as well as from new ones arising from constantly 

 changing conditions, especially about the towns — the 

 building of a railroad, the making of a drive, the block- 

 ing of an outlet to water by the washings of a storm or 

 the falling in of some excavated materials, the building 

 of a new house whose waste water is' not properly cared 

 for, these and a hundred others are exigencies which re- 

 quire an interest in the subject and a careful and minute 

 watchfulness." 



Mr. Pergande's interesting discovery that they breed 



