112 TURNIP. 



black ones. . . . They jump on being approached, and so are difficult 

 to get, or I might have sent you a specimen. 



" So numerous were they on some fields, that as one approached 

 them they rose before one like a little cloud. They have all but 

 disappeared now" (July 24th. — E. A. 0.). " They may have been 

 here in former years, but I never observed them, and they could not 

 have done so much harm without being noticed." 



Still (from the difficulty of capturing these minute leaping creatures) 

 I had no specimens ; but on the 30th of July, Mr. Ironside forwarded 

 me a good supply, captured by placing the open mouth of a phial over 

 the Springtail, and with these he wrote further : — " I send by this 

 post a few specimens of the pest we were concerned about among the 

 Turnip plants. I got them all below the leaf, but I saw a few on the 

 upper side, which suddenly jumped away on my approach. They are 

 not nearly so numerous as they were, and not quite so keen, as I had 

 no difficulty in approaching them. I put the mouth of the phial over 

 the insect, and touched the top side of the leaf, and they jumped right 

 into the bottle. ... I have sent you leaves of the Swedish and of 

 the common Turnip to show you the dishealth existing." 



Later on, that is, on the 20tli of August, Mr. Ironside wrote me 

 that he had been making several examinations of the Turnip-leaves in 

 order to feel certain that it was the Springtails that were nibbling the 

 under siJe of the leaf, and now considered that it was these creatures 

 that were nearly the whole cause of the mischief. 



Mr, Ironside remarked : — " It is not always one can catch them at 

 their work, as one cannot see them without taking the leaf up, and 

 they are thereby apprised of your presence, and the forked tail promptly 

 used. I am also strongly of opinion they thrive in moisture (and 

 quite unlike the Turnip Beetle in that respect). I said to you in a 

 former note that the Springtails were disappearing ; I now find they 

 are not, but are present in all sizes ; this makes me think that the 

 extremely wet weather we are having is conducive to their existence." 



The specimens sent me were quite certainly of the genus Smyn- 

 thiiriis. This genus is distinguishable by the globular form of the 

 creatures, also by the antennae (or horns) being four-jointed, with the 

 terminal segment longer than tbe others. 



With regard to the precise species, the specimens sent me agreed 

 so well in colour, shape, structure, and measurement (so far as I could 

 follow up the points with a quarter-inch microscopic power) with the 

 description given by Sir John Lubbock ■■:■ of the Smynthnrus luteus, 

 Lubbock, that I do not see any reason to doubt their being of this 

 kind. 



* See ' Monograph of CoUembola and Thysanura,' by Sir John Lubbock, Bart., 

 p. 108. 



