ACTING STATE ENTOMOLOGIST. 
49 
that had been operated on by Mites, I did not count, nor did I estimate them separately 
from each other; for, up to this day, I had not become aware of the nice distinction 
between last year’s scales, containing white egg-shells, and scales recently gutted by 
Mites, which contain yellowish egg-shells. But I estimated the whole number of matured 
scales, containing no living and plump eggs, at several hundreds. After the above 
process had been gone through with, which necessarily obliterated or removed many 
of the young Bark-lice killed by the soap, I counted 422 dead Bark-louse larvae still 
adhering to the bark, with the “ anal sack' ’ not at all developed , and most of them without 
even a “medial scale,” the great bulk of which must therefore have been killed by 
the soap while still in the larva state. If we assume that 22 of these were males — 
which is a rather large estimate — and deduct these from the total, we get 400 female 
bark-lice killed by the soap, to 7 that survived the operation of the soap; or, which 
is the same thing, out of the whole number of females 98 % per cent, killed. It is 
possible, however, though not at all probable, that the seven female Bark-lice that 
survived might have been late-hatched individuals, that crawled down, before they 
became stationary and after the soap was applied, from the small, terminal twigs that 
I neglected to soap. In this, as well as in the other three experiments already detailed, 
the portion of the branch examined under the lens was altogether too far removed 
from the main limb which was not soaped, to allow of any considerable number of 
Bark-lice crawling on to it from the main limb ; and besides, when all these experiments 
Ayere tried, the great bulk of the Bark-lice had certainly become stationary. 
Dr. Mygatt tried the same experiment about the same time of the year, but used a 
muc 1 weaker solution of soap, which seems not to have been quite so effectual. “ One 
trr he informs us, “ was treated with soap-suds, two tea-cupfuls of soft soap to a 
p<. tf water. Every part was wetted by immersing the ends of the branches and 
uf g a syringe. The leaves and young growth became yellow, but were not destroyed, 
ii : t of the lice were killed, probably half or more.” ( Transactions Illinois State Agvi¬ 
ew :i , al Society, I., p. 516.) 
Oq Nov. 7th, 1867, the scales being now of course fully matured, I made a still 
stronger solution of the same soap, namely one part by measure of soap to four parts of 
ws r, and applied it when warm with a very soft shaving brush to a branch prepared 
a- ^abeled as in the other experiments. On Dec. 5th, I cut off a portion of this limb 
ar ’ 'xamined the scales under the lens. From some cause or other, upon this limb, 
\ a was upon a different part of the same tree and not so badly infested, the Mites 
ha. iot operated at all, so far as I could discover. After lifting and examining several 
scores of scales, and finding that every one of them without exception contained good 
plump, healthy eggs, I became fully satisfied that the soap had not in any wise affected 
the vitality of the eggs, and did not think it worth while to continue the examination. 
The weather during the whole of November had been remarkably mild and genial and 
dry ; and, from my experience with the eggs of this and other insects, I am sure that, if 
these eggs had been killed by the soap, they would have shriveled up to nothing in 
much less than a month of such weather. But be this as it may, I shall be able to 
ascertain in the spring of 1868, from the portion of the branch that remains on the tree, 
whether these eggs that were soaped in November will hatch out as usual in the follow¬ 
ing spring, or whether some or all of them were killed by the soap. 
From the above facts, I infer that soap will kill Bark-lice when they are very young, 
but has no effect whatever upon the matured scale.* 
* Since the above was written, Dr. Mygatt has informed me that pure, undiluted soft soap is largely 
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