amerigAna 



VOL. VI. 



BROOKLYN, MAY, 1890. 



No. 5. 



On the Probable PoUenization of Greenhouse Chryan- 

 themums by Eristalis tenax. 



BY JOHN HAMILTON, M. D. 



In many of the greenhouses throughout the United States, 

 where Chrysanthemums are anywise extensively grown, a Dipteron, 

 known to the proprietors as the Chrysanthemum fly or bee, makes 

 its appearance early in October on the disclosing of the first flowers 

 and continuing as long as the Chrysanthemums are in bloom. Its 

 appearance and actions so greatly resemble those of the honey bee 

 as to pointedly exemplify a mimicry that is all protective. I first 

 observed it five years ago, in considerable numbers, on the large 

 collection of Chrysanthemums in the greenhouses of the Allegheny 

 parks; in many respects it acted very bee-like, hovering over the 

 flowers till a selection was made, then alighting and burying itself 

 among the i:)etals, it would work among them diligently for a time 

 and then fly away to another. From Mr. William Hamilton, the 

 learned superintendent, I obtained the information that this fly was. 

 reputed to pollenize Chrysanthemums, and that this knowledge had 

 been utilized by certain growers of seed, though he himself had 

 never experimented to obtain any in that way. The fly does not 

 meddle with any of the other flowers in the greenhouse, however 

 fragrant, nor has it been seen outside by any of the operatives, nor 

 by myself. 



Mr. John Thorpe, of Pearl River, N. Y., a learned and distin- 

 guished florist, who makes a specialty of Chrysanthemums, to -whom 

 I wrote for information, courteously states that he has not noticed it 

 outside his greenhouses at any time, and neither has he seen it until 

 the first Chrysanthemums are in bloom, the date varying from Octo- 

 ber 5th to 13th, in six years; and further says, " I am sure they as- 



Entomologica Americana. Vol. VI. 5 May, 1890. 



