THE UP-WINGED FLIES. 119 



In taking, first, the most important order of 

 naturals (the Ephemerida family), we deal with what 

 has hitherto been made a most intricate and formid- 

 able list of insects, modern naturalists dividing and 

 sub-dividing into sections and sub-sections until the 

 poet Pope's " thousands of winged insects " threaten 

 to descend from the ideal into stern reality. Personal 

 observations, extending over a period of fifty years, 

 leads us to affirm the greater part of this extensive 

 classification to be perfectly needless. There are, in 

 fact, but four different species of Up-winged insects, 

 these forming the Ephemeridce family. The prevail- 

 ing temperature of the atmosphere and the water at 

 the time of the larva and pupa arriving at the stage 

 of maturity, is largely instrumental in influencing the 

 colour, the body of the insect particularly being 

 susceptible to change from these effects. 



The four species here referred to are the ordinary 

 Olive and Iron Blue Duns, the Large Browns, and the 

 May-fly or Green Drake. 



The Olive Dun makes its first appearance in 

 February, when it is known as the Blue Dun, or 

 February Flapper. It then presents a dead lead 

 colour, the inclement weather then seasonable causing 

 the fly to assume so sombre a hue. A few weeks 

 later, if the weather be more genial, it is a shade 

 lighter upon the body, when it is styled the Cock- 

 winged Dun. By the beginning of April it is of a 

 general olive colour, with yellow-ribbed body, upon 

 which rests a bloom, like that of a ripe muscat grape, 

 but upon dull days this is substituted by a rust-like 



