200 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



that others are too costly for use, even in this way. One or two 

 promising substances have been found, however, and farther tests of 

 these will be made during the coming season, as it is, of course, unwise 

 to rely upon the results obtained in a single year. 



Mr. Herbert Osborn : Have you noticed any effect of dry season 

 On the breeding of onion thrips and does a dry season show any reduc- 

 tion in the injury caused by this insect? 



Mr. H. T. Fernald : Dry seasons may check the injury to a certain 

 extent after a time, but at first the insects seem to increase rapidly. 

 At one time I thought this insect was distinctly a dry season species. 

 Later it did not seem to be affected so much by dry weather. 



Mr. Herbert Osborn: My experience has been that it migrates 

 into onion fields during the dry periods. 



Mr. H. T. Fernald: Dry weather usually begins in New England 

 about the 1st of July and at that time our onion fields are so thoroughly 

 stocked with thrips that no further migration to them is necessary. 



President P. J. Parrott: Is this species a common pest on cab- 

 bages in Massachusetts? 



Mr. H. T. Fernald: I have not noticed it to any extent. 



President P. J. Parrott: As regards the maggot, Mr. Schoene 

 has been working with a similar insect which attacks cabbage, and has 

 found that carbolic acid emulsion is not a satisfactory treatment. We 

 rely on screening the seed-beds to protect seedlings. 



Mr. W. D. Hunter: Has anyone tried naphthaline? This sub- 

 stance has been found to be very destructive to several species of root 

 maggots. I have tried it on cabbage, turnips, and radishes, but not 

 on onions, and it gave the plants practical immunity. 



A member : I have tried naphthaline alone and in combination with 

 other materials and found that it controlled both the maggots and 

 the growth of the plants. 



President P. J. Parrott: One of our cabbage growers has made 

 it a practice of planting a moth ball with his early cabbages. 



Mi . W. J. Schoene : The cabbages do not grow very well, however. 



Mr. Henry Skinner: Naphthaline might be used in the liquid 

 form. It is one of the best materials to use for household insects be- 

 cause it can be applied so as to seal every hiding place. 



President P. J. Parrott: The next paper is entitled "A New 

 Destructive Cutworm of the Genus Porosagrotis Occurring in Western 

 Canada, " by Mr. Arthur Gibson. It will be read by Doctor Hewitt. 



