Ill 



loosely constructed, and in these cases the 2 ounces of bisuli^hido used 

 had not been eiiective against the lice. Mr. Howard stated that Gar- 

 man's original suggestion of the use of a washtub which wouhl inclose a 

 vine of considerable size by drawing in the runners was a very practi- 

 cal one, especially in the case of small garden patches. Mr. Smith 

 urged the advisability of very i^rorapt action in the case of the melon 

 louse, instancing the comparative ease with which it could be stamped 

 out when it first appeared ou young plants having but three or four 

 leaves. This, he said, would i-equire a very much smaller covering and 

 less bisulphide. He also thought it x)ossible that i)aper boxes could be 

 obtained very cheaply in nests, and could be employed to inclose the 

 vines. Mr. Saunders said that paper caps were made for the use of 

 farmers, to protect their haycocks, and he thought the same factories 

 would make smaller caps for the use suggested by Mr. Smith, and prob- 

 ably at a very slight cost. In reply to a question by Mr. Hopkins as to 

 the effect of bisulphide on the natural enemies of the Aphis, Mr. Smith 

 replied that he placed no importance whatever on the action of natural 

 enemies, and was quite indifferent as to the effect of the applications 

 on them, believing that natural enemies were rarely, if ever, of any 

 economic importance, or appeared in numbers sufficient to keep injuri- 

 ous insects in check until after the main damage had been done. Mr. 

 Marlatt referred, in this connection, to the frequent receipt by the 

 Department of Agriculture, during July of the present year, of samples 

 of leaves of melon covered with aphides, which were in every instance 

 so extensively parasitised that scarcely an unaffected louse could be 

 found; and he urged that this seemed to be a case of very substantial 

 benelit accruing from the presence of parasitic enemies. 



Mr. Smith again stated that the i)arasite was, generally speaking, 

 too late in its appearance, and that great injury was always done 

 before nuy effective stay in the multiplication of the pest was brought 

 about. 



Mr. Howard said that one practical point, at least, resulted from 

 the presence of the i)arasite as described on the samples referred to, 

 and that was that it obviated the necessity of detailing any remedial 

 treatment in reply to correspondents sending such samples, it being 

 only necessary to state that by the time the reply was received the 

 insect pest would have been entirely exterminated by the parasite. 



Some general discussion of the relations of parasites to injurious 

 insects followed. Mr. Howard wished Mr. Smith, in his future work, 

 to note the exact temperature and the effect of heat on the aphides, 

 referring to the occasional sudden destruction of these insects by the 

 very warm July days in Washington. 



Mr. Saunders suggested experimenting to determine the relative 

 eff'ect on plants of rapid evaporation of bisulphide on hot earth or 

 sand, or the probably slower evaporation on cool soil, or the still 

 slower evaporation in graduates. 



