THE MARGUERITE FLY OR CHRYSANTHE- 

 MUM LEAF MINER. 



{Phytomyza chrysanthemi Kowarz.) (Order, Diptera; Family, 

 Agromyzidce.) 



M. T. SMULYAN, B.S. ^ 



INTRODUCTION. 



The growing of plants under glass is an important industry in Massa- 

 chusetts, and is becoming more so every year. Among the plants which 

 are of ornamental value, or are raised for their flowers, marguerites or 

 daisies, chrysanthemums and other Compositse are very generally grown, 

 the two former often on a large scale. It is not at all surprising, then, 

 that complaints are heard on all sides regarding the ravages of the Mar- 

 guerite Fly, or Chrysanthemmn Leaf Miner. Indeed, in many instances, 

 the commercial growing of marguerites and some other Compositge has 

 been given up on account of this pest. 



At the time the writer began the investigation of this troublesome in- 

 sect it was not generally known that there were one or two florists in the 

 State who possessed a satisfactory method for its control, though such was 

 the fact. 



The investigations upon which this paper is based were carried on in the 

 insectary and laboratories of the Department of Entomology of the Massa- 

 chusetts Agricultural College, Amherst, under the direction of Prof. H. T. 

 Fernald and Dr. G. C. Crampton. The investigations were begun early 

 in February, 1913, and continued to July of the same year, in connection 

 with the marguerite, or cultivated daisy, as a food plant. Some additional 

 data relating to the hfe history of the insect were collected during the 

 following November. The thanks of the writer are due both to Professor 

 Fernald and Dr. Crampton for their interest in the work, and for a number 

 of valuable suggestions. The writer is also under obUgations to Mr. 

 Walker Holden of Andover for furnisliing infested marguerites for study, 

 and to the latter again and to Mr. W. R. Nicholson of Framingham for 

 their readiness in answering questions, many of the answers proving very 



helpful. 



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1 Contribution from the entomological laboratory of the Massachusetts Agricultural College. 

 Part of a thesis for Ph.D. degree. 



