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44 
the case is none the less interesting, as showing that parasitic in¬ 
sects, even of the most minute character, can be transported, in 
some instances, with perfect ease and certainty, and should cau¬ 
tion us against dismissing the whole subject from our minds, as 
we have been inclined to do, as impracticable and absurd. 
POSTSCRIPT. 
Since writing the above, my friend Capt. Edward H. Beebe, of 
Galena, procured and transmitted to me (Nov. 8) a number of 
apple twigs, obtained partly in that town and partly from the 
Southern part of Wisconsin, a section which has suffered more 
from the depredations of the Bark-louse than almost any other 
locality. A very brief inspection of these twigs was sufficient to 
show that our infinitessimal friend, the Chalcis, has not yet found 
its way to that region, or at least not to that particular locality. 
Not a trace of it could be discovered, either by the round holes in 
the scales or the presence of the larvse beneath them. The dis¬ 
appointment, however, was somewhat mitigated by finding that 
more than two-thirds of the scales are, nevertheless, from some 
cause or other, abortive. Upon carefully raising and examining 
two hundred scales upon six different twigs, sixty of them were 
found to contain sound eggs of the Bark-louse, and one hundred 
and forty were abortive. These abortive scales present the same 
appearances that such scales have when obtained from other lo¬ 
calities ; that is, a small proportion of them contain only the thin 
and dried remains of the female Bark-louse, who has perished 
from some cause, without depositing or perhaps even forming her 
eggs. But most of the scales exhibited the brownish, granulated 
mass which they generally contain, and which we may presume 
to consist of shrunken and discolored eggs. This mass of debris 
also has, in most cases, a furry aspect, which is probably owing 
to mould. 
The interesting question here arises, what, in the absence of 
the Chalcides, has caused the destruction of this large proportion 
of the bark-lice and their eggs ? I searched carefully for Acari , 
and lest, from their minute size, I might overlook them with a 
common lens, I put many of the scales under the microscope, but 
did not detect more than half a dozen in all; just enough, how¬ 
ever, to show that they are not altogether absent. All the phe- 
