16 
It will be seen that the cold of the winter in question was as efficient 
as an ordinary treatment with the best of our insecticides. 
‘Tn the latitude of Washington and southward the result of unusual 
cold is apt to be much more noticed than in more northerly latitudes, 
where the temperature conditions of winter are more uniform. From 
Washington southward the multiplication of many species of scale 
insects is checked only for a very short period by cold weather, or, at 
least, the breeding continues until December, or even into January, 
and this renders these insects in such latitudes especially liable to 
destruction by any sudden and unusual falling of temperature. 
There is probably another reason, also, which acts in the same way, 
namely, it is to be inferred, and the experience of last winter rather 
corroborates this belief, that the scale covering secreted by the insects 
in warmer latitudes is less dense and furnishes less protection against 
sudden changes in temperature than in the case of the same species 
farther north; and this, in connection with the absence or great reduc- 
tion of the resting or hibernating period. will undoubtedly account for 
the complete killing out of the scale insects here and there throughout 
the South, as has rather frequently been brought to our notice. 
Such conditions may often be very local and perhaps sufficiently so 
to explain the almost complete extermination of scale insects in a par- 
ticular orchard in such weather. Itis not an unfamiliar experience on 
the Eastern Shore of Maryland, for example, that the cold-air waves 
are so restricted in area that a single orchard or series of orchards in a 
single line of territory of not exceeding a mile or two in width will 
have the fruit buds killed, while neighboring orchards on either side 
of this strip escape uninjured. 
The fact is frequently noted that scale insects sent to this office for 
determination are practically all of them dying under natural condi- 
tions, and while the inference is a very natural one tbat they have suc- 
cumbed to some disease, this does not seem to be the necessary and 
invariable explanation, and there is no doubt that very often some 
adverse climatic or temperatureconditions have been the cause. Almost 
any dead scale insect attracts saprophytic fungi, and examination of 
such material nearly always shows fungus mycelium. Undeubtedly 
most of the saprophytic fungi gain access to the insects after the limbs 
bearing them have been removed from the plant and the insects are in 
a dead or dying condition. 
AN ACCOUNT OF ASPIDIOTUS OSTREAFORMIS. 
By C. L. Maruatt, Washington, D. C. 
In an article in Science for July 7, 1899 (pp. 18-20), the writer gave a 
preliminary account of a European scale insect enemy of deciduous 
trees, which had apparen*ly recently been introduced into the United 
States and was rather rapidly spreading and becoming established. 
