228 ENTOMOLOGICAL NEWS. [Sept., 'O2 



ing, January 3, 1902. The only explanation that suggests 

 itself is that the frequent light rains, though they were not 

 heavy enough to remove the soluble compounds, dissolved 

 them sufficiently to destroy the young before these could form 

 the protecting scale. The dead young scales vary considerably 

 in size, suggesting that the larger ones emerged soon after one 

 rain and the smaller ones just before the next. 



The weak point in the life history of Diaspis pen tagona Targ. , 

 is the fact that the scale is formed very slowly, for some time 

 consisting simply of long, irregularly matted, waxy filaments 

 easily penetrated under the influence of rain. Whether the 

 young of species like Aspidiotus aurantii Maskell and A. per- 

 nidosus Comstock, which form a dense scale in a few days, can 

 be destroyed in the same way is an interesting point that has 

 not yet been determined. 



It is clear, however from Californian experience, that lime- 

 sulphur-salt wash is effectual against Aspidiotus pcrnidosus 

 Comstock in that State. Different experimenters have re- 

 ported it to fail under the climatic conditions of the Eastern 

 States, but it seems likely that results were looked for too soon 

 and observations discontinued before the wash actually became 

 operative. Even though the results at first may be apparently 

 negative, it seems quite possible that the after effect on the young 

 scales of applications made just before the buds unfold will give 

 results comparing favorably with those attained in the West. 



Strangely enough, maii3 r of the old scales on the trees treated 

 in the tests described are still alive and ovipositing, the young 

 continuing to emerge but still failing to settle successfully. 

 This great irregularity in development, together with the 

 almost perfect protection by the scale, is the strong point in 

 the life history of the species. On trees thoroughly sprayed 

 with either lime-sulphur-salt wash or sheep dip, the only hope 

 of survival seems to depend on the ability of the old scales to 

 hold out until the rains reduce the soluble compounds of the 

 wash sufficiently to render them harmless to the young. 



Owing to martial law regulations it has not been possible to 

 keep full notes on the tests made at Simondium, but the avail- 

 able records are in harmony with the observations made at 



