56 THE ENTOMOLOGIST. 
of iron or steel,* but I cannot myself advise the use, for pinning 
through an insect, of a pin made of this metal; it being my 
experience that this metal is subject to decay in the interior of 
the insect, so that the pin frequently, though looking perfectly 
sound, breaks in two in the interior of the insect. 
In connection with this it must be recollected that the interior 
of an insect is liable to contain various acids according to the 
nature of the species, the maturity of the specimen, and the way 
in which it has been killed and dried. 
As yet I have never lost a specimen pinned with the silver- 
wires of my own manufacture. The wire soon loses its bright 
white appearance, tarnishes and becomes even quite black, but I 
have seen no reason to suppose that this change extends into the 
interior of the pin, nor have I found that the wire is at all 
affected by acids in the interior of the insect: certainly there 
has never been a trace of verdigris. 
It is generally supposed that silver-wire is too flexible to be 
used for such a purpose. This is due to the fact that the wire 
usually used in arts is annealed. The unannealed wire, on the 
contrary, is quite rigid enough for entomological purposes. It 
does not, however, take so perfect a point as steel does, and when 
insects are pinned at home with it, I recommend that a very 
minute prick should first be made with the point of a bead-needle 
at the spot in which the insect is to be pinned with the wire ; one 
of the wires should then be taken between the ends of a pair of 
delicate pinning forceps and passed through the insect, starting 
at the minute prick previously made. If the insect to be impaled 
is large enough to be held between the finger and thumb of the 
left hand this should be done, and the impaling wire should be 
put in with a screwing motion; by this means the risk of 
rupturing or splitting the undersurface as the point of the pin 
emerges is very much reduced. If the insect be not large enough 
to be held in the fingers, it should be placed on a piece of velvet 
or soft cloth, which assists both in steadying it, and in 
supporting the undersurface when pressed on by the emerging 
point. 
After the insect has been impaled it should be pinned on a 
block composed of a surface of card with cork or pith underneath 
the card so that the cork or pith is not seen. The neatness of 
the appearance of such insects in a collection depends chiefly on 
these blocks. A system of symmetrical sizes should be used, and 
after many years’ trial I can recommend the following sizes for 
the blocks as suitable, viz., No. 2, 12} by 83 mm.; No. 3, 173 
by 124 mm.; No. 4, 25 by 174 mm.; No. 5,35 by 25 mm. 
Hach of these sizes is double of the one that preceded it, and in 
each the length is to the breadth as 7 is to 5. The locality and 
date should be written on the card forming the upper surface of 
* Steel, black-enamelled.—R. 8. 
