1920 



ENTOMOLOGICAL SOCIETY. 



35 



Table IV — Effect of LimbmSulphuk, 1-7, 1.037 sp. gr. on Psylla Eggs. 



* On the Point of Hatching. 



As shown in the foregoing tables, lime-sulphur is most eJEfective as an ovicide 

 when used at the strength of 1-7. The tables also show that the newly-laid eggs 

 are on the whole more readily destroyed than those on the point of hatching. 



In the experiments with lime-sulphur 1-8 and 1-9 it was observed that fre- 

 quently a large percentage of the eggs would hatch. However, the spraying 

 mixtures apparently had weakened the embryos or nymphs within the eggs to 

 such an extent that in emerging or immediately after emerging they succumbed. 



In the tests where lime-sulphur 1-7 was used 100 per cent, of the eggs in- 

 variably collapsed. 



Lime-Sulphur and Starch. 



An effort to increase the ovicidal value of the weaker lime-sulphur sprays 

 by adding starch to them in order to make them spread and stick better met with 

 success. (See Tables Nos. 5, 6, 7.) 



Table V — Effect of Lime-Sulphur 1-10 plus 2 lbs. Starch to 40 gals, on 



PsyUla Eggs. 



Table VI — Effect of Ljme-Sulphur 1-9 plus 2 lbs. Starch to 40 gals, on 



PsYiXA Eggs. 



