1905-1906.] The " Water-Flea " Scare in our City. 271 



But now, to come to the point, what is the " flea " of the 

 present invasion ? Amid the multiplicity of organisms said to 

 have been found of late in the water-cisterns of the city, one 

 mysterious visitant in particular has been largely in evidence. 

 This is the so-called " water-flea " which has been the innocent 

 cause of so much alarm and so many columns of print. De- 

 scriptions of it, scientific and otherwise, have not been wanting. 

 Some of these descriptions furnish rather amusing reading. 

 Thus a Southside doctor, who had specimens sent to him from 

 the Sanitary Department, says : " They are of a yellowish- 

 white colour, with four legs, two abortive wings, and a 

 peculiarly-shaped head. The body is semi-developed, is of a 

 hard substance, glossy and shiny in appearance." Further, to 

 show these strange creatures do not favour any particular 

 situation, the writer adds, " They have been discovered in new 

 cisterns, old cisterns, area cisterns, and cisterns situated in 

 house-tops." The same insect was observed in Edinburgh 

 water, it appears, about ten years ago, and the rather remark- 

 able statement is made that " this time they are larger in size 

 than they were on the former occasion " ! Then we have the 

 one " scientific " observation added, that " when treated with 

 ammonia vapour or sulphurous acid vapour, they die almost 

 instantaneously." Yet this learned observer does not venture 

 to give the " flea " a name. We now know, however, that it 

 is the spring-tail with which we have to do. Numerous 

 specimens have been seen by those able to identify it. 



There is not much mystery about spring-tails, as they are 

 common enough, and their life-history is fairly well known. 

 In the ' Monograph of the Collembola and Thysanura,' by Sir 

 John Lubbock — now Lord Avebury — published by the Eay 

 Society in 1873, the first attempt in this country to classify 

 the group was made. The result, however, has not been quite 

 satisfactory : minute structural differences, on which classifica- 

 tion frequently so much depends, are, unfortunately, scarcely 

 noticed ; the nomenclature is often very puzzling ; while the 

 localities given are almost wholly English — one reference only 

 to Scotland being made ! Following upon the excellent later 

 work of a few North-European scientists, we owe much to Messrs 

 Carpenter and Evans for the valuable observations made by 

 them regarding the Collembola and Thysanura of Scotland in 



VOL. V. s 



