67 
by your instructors, should be the means of greatly stimulating 
this feeling of emulation amongst the students. In Part I. of my 
new book I have given some brief instructions for the collecting 
of insects and the preservation of the same; and, if anything 
further bearing upon the subject be required at any time, it can 
be had for the asking. 
Our young man may now be supposed, with the aid of a few 
pounds in cash, a fair stock of common sense, diligence, and a set 
of garden appliances, including a good spray-pump, to have made 
a fair start. His trees have been well selected from advice 
supplied, probably by either our friend, Mr. Neilson, or other 
experts. ‘The chemist, we will suppose, has been asked to furnish 
some particulars as to the soil and its constituent parts, and the 
work may be fairly said to have commenced. 
The trees thrive well and show signs of permanency, when lo! 
our young friend detects something wrong with his trees, which 
are either looking sickly or display signs which, to the practised 
eye, are not to be mistaken, of some pest more or less insidious in 
its attacks upon the tree. What is best to be done? Having 
thought the matter over, he determines to seek advice either from 
his books or from those whom a paternal Government have 
appointed for such work. He sends down specimens, obtains the 
necessary information, and all appears to be well. It is here 
where a practical knowledge of these diseases makes itself apparent. 
He discovers, for example, that his peach trees are covered with 
little brown insects with longish antenne (or horns), with two 
projections sticking out from near the extremity of the body. 
Now the person who does not know, or has not read anything 
about the nature and habits of this pest, often says to himself— 
“Ah! I have heard somewhere of Paris green. I will give 
my tree a good dose, and so surprise our little brown friends.” 
He gets the London purple or Paris green and sprays his trees ; 
the result being that he finds the aphides there as usual, and not in 
the least disconcerted by what he considers his remarkably 
ingenious device for their destruction. Why and how is this? 
I will endeavour to tell you. 
The aphides, as well as the very large family of so-called plant- 
bugs, are wholly suctorial in their habits, that is, they have a 
rostrum or beak with which they pierce the bark, and through 
which the sap of the tree is sucked out. It will thus be seen that 
such useful preparations as the arsenical compounds are next to 
useless against the above-mentioned insects, as their “beaks” are 
thus far below the reach of such applications. 
The man who has studied the habits of these creatures for 
himself knows this much, and proceeds to destroy the hordes of 
little insects by spraying with a liquid that will kill by coming 
into contact with them. (I need hardly tell you what to use, as 
EZ 
