386 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



in a laboratory, the infested apples being placed upon desks safe from 

 the direct rays of the sun. The daily maximum temperature of the 

 room during the tests ranged from 64° F. to 71° F. All eggs were 

 examined at least once a day and the appearance recorded.^ The 

 maximum temperature outdoors ranged from 55° F. to 72° F. 



On September 24th all eggs that had failed to hatch were examined 

 to ascertain, if possible, the condition of the embrj^o at death. When 

 the embryo appeared hard and dry it was recorded as "dried." When 

 the contents of the egg were watery the egg was recorded as ''crushed." 

 This was undoubtedly the case in some instances but the term is used 

 in the absence of a certain knowledge of the cause of death. Embrj^os 

 apparently normal but in which the development ceased before hatch- 

 ing was complete were recorded as "dead." These terms are indefi- 

 nite and signify nothing more than merely the appearance of the egg 

 contents. 



At first an attempt was made to spray the apples by means of an 

 atomizer. This method was given up as a failure because the spray 

 collected in drops covering only a small portion of the surface of the 

 apple, in which case the egg was more frequently missed than hit. 

 When the drops of spray were too large they would roll from the apple 

 leaving a practically dry surface. The same would frequently occur 

 upon shaking the fruit. This was the first indication in the experiment 

 of the inefficiency of a lime-sulphur spraj^ for killing codling moth eggs. 

 The failure of a spray to cover the eggs deposited on the fruit is suf- 

 ficient to exclude it as a codling moth ovicide regardless of its efficiency 

 in the laboratory. 



The method adopted was to place a drop of the spray material di- 

 rectlj^ upon the egg. If, then, with such treatment the insecticide 

 failed, then the results would be doubl}^ conclusive. 



The eggs were divided into four lots. One lot remained untreated 

 as a check. A second lot received a treatment of a one-to-30 dilution 

 of lime-sulphur testing 30° B.- A tlfird lot received lime-sulphur 



1 The appearance of the well known "red ring" and "black spot"; when the 

 larva was visible throught the chorion with a hand lens the appearance was recorded 

 as "larva." 



2 The author frankly admits that this specification of the "strength" of lime-sul- 

 phur, so often encountered in the literatm-e, signifies absolute! j' nothing. It is true 

 that the dilution is certain and known and if a chemically identical lime-sulphur 

 concentrates were diluted similarly then the biological results would, under similar 

 conditions, be similar. But all 30° B. lime-sulphurs are by no means identical or 

 even approximately so. Nor does it make matters any clearer to obtain an anah'sis 

 showing the amount of total sulphur or total sulphid sulphur. Such data give no 

 more definite idea of its efficiencj' as an insecticide (or, for that matter, as a fungicide) 

 than a mere statement of its density. The reason for this uncertainty lies in the 



