76 Forty-first Report on the State Museum. 



Eupatoriums, Gazanias, Helianthus muUiJiorus, and, as above mentioned, 

 Cinerarias. These, at present, are about all the composites within its 

 range. I have not observed it on any other order of plants. 



Localities. 

 In addition to its presence at Dosoris, the insect is also operating in 

 the greenhouse of Mr. T. L. M. Barlow, at Glen Cove Landing, and in 

 the greenhouses at Queens, L. I., and at Hinsdale ^^ a station on the 

 Long Island Eailroad, about fifteen miles from New York city. 



Importance of Arresting its Spread. 

 It will be readily seen that from the prolificacy of this new insect 

 pest, and the character of its injury to the foliage of the plants of the 

 favorite and extensive family which it claims for its food, that it will 

 prove, both to florists and lovers of flowers generally, an unwelcome 

 addition to our insect fauna. It would, therefore, be well, if earnest 

 and persistent and a successful effort can be made for destroying it in 

 the limited locality to which it seems for the time restricted. It 

 should be borne in mind that almost without exception, newly-intro- 

 duced insect pests display a wonderful ability to inflict greater injuries 

 in their new home than they were wont to do in their old. Up to the 

 present, we only know this fly as a greenhouse pest. Should it be 

 found hereafter continuing its propagation during the summer months 

 in the garden, a great increase of harm would be the result from the 

 large number of our valued Compositce that w^ould then be exposed to 



its attack. 



Remedies. 



Leaf -miners, like the numerous larvae that find secure shelter within 

 their burrows in plant-stalk and tree-trunk, or beneath the surface of 

 the ground, are almost wholly beyond the reach of our best insecti- 

 cides; and when occurring in large numbers, as does the Marguerite 

 fly, it is useless to attempt to fight them by any of the ordinary appli- 

 cations which the economic entomologist is accustomed to recommend 

 against the larger and more vulnerable class of exposed insects. 

 Experiment can alone show the best method of meeting this newly 

 introduced greenhouse pest. Perhaps vessels of diluted molasses and 

 vinegai% or other liquid developing fermentation, placed in flat vessels, 

 would attract the flies and drown them as soon as they emerge from 

 pupte and before they are in readiness to deposit tbeir eggs. But, 

 until some other successful method can be found, it would be best to 

 examine the plants at brief intervals after the first recognition of the 

 attack, and pick off every infested leaf and burn it. This, we learn, 

 was done at Hinsdale in early winter, with the result of arresting the 

 attack and securing a full bloom. Crushing the larvae between the 

 thumb and finger, as sometimes recommended, would prove too slow 



