546 JOURNAL ()I<^ ECONOMIC ENTOMOLOGY [Vol. 9 



soil was saturated with solutions of lead arsenate, Paris green and the 

 like. 



Two series of experiments were employed in the above; one with 

 potted plants, soil of which contained maggots, and another in which 

 slices of potato covered with the maggots were embedded in pots of 

 sawdust, thus making simple the observations of the effects of the 

 material used. The results in all of these cases either failed to kill the 

 maggots or injured the plants. 



It may be worthy of note here that Hart reports that a solution of 

 from one-half to six per cent of nicoteen brought about premature 

 emergence to the flies, thereby destroying them. He also states that 

 the preparation repelled the larvae. His work was with cucumber 

 beds in a forcing house. The trouble here arose through the use of 

 comparatively fresh manure as a fertilizer. He noted in this connec- 

 tion that when the manure was well rotted little or no injury followed. 



It is to be hoped that the work now being done in various labora- 

 tories with nitrobenzine will lead to the discovery of some satisfactory 

 applications for killing underground insects. 



Destroying the Adults 



Many flies were killed by the use of the following recommended by 

 Sanders in "Minnesota Insect Life": 



One-sixth ounce of sodium arsenate dissolved in a gallon of water and 

 a pint of molasses. The flies preferred this mixture to combinations 

 of it with stale beer and orange juice. The plants were allowed to 

 become dry and then the sweetened mixture was sprayed over them 

 with a syringe. They fed upon it greedily. However, under ordinary 

 conditions, complete control could not be effected for the flies were 

 not strongly attracted to it. 



We had hoped to try the paradichlorobenzine so strongly recom- 

 mended a year ago, but have been unable to obtain it even for experi- 

 mental purposes. 



Natural Enemies of Sciara Flies 

 In two references in literature that have come to our attention, 

 certain Sciara maggots have been accused of parasitism. Mr. Peter 

 Cameron 1875(3) declares them to be internal parasites of Sawfly 

 larvae. He states that the latter retain sufficient vitality to spin a 

 cocoon inside of which the fly larvae completes the destruction of 

 their victims. Later, they quit the cocoon and change to pupae in the 

 ground. 



Much later than this, Sciara was credited with preying upon Hessian 

 fly puparia. If these cases are authentic, it is a step beyond the 

 usual scavenger tendency we have so often observed. 



