ENTOMOLOGICAL PINS. 65 
pins. Entomological pins are, in fact, extremely unsettled in 
their characters. I have had insects, nearly a hundred years old, 
that have been transferred again and again, and yet the pins 
they are transfixed with appear to be in perfectly good condition, 
and capable of standing wear and tear for another century or 
two. On the other hand, specimens only a few years old are 
frequently lost either by the insect splitting asunder from the 
development of verdigris, or from the pin breaking in two from 
corrosion. 
This uncertainty arises, I believe, from two different sources, 
viz., differences in the pin-metal, and differences in the substances 
in which the pin is placed. This last source of evil is also of a 
double nature, the corrosion being sometimes due to the nature 
of the substances in the interior of the insect, and sometimes to 
the articles with which the box is lined, viz., the paper, the 
matter with which the paper is fastened to the bottom, and the 
substance, cork or other material, forming the bottom of the 
box. To these various sources of deterioration of pins must be 
added the atmosphere of the apartments in which collections are 
kept; it being according to my experience an undoubted fact 
that in a damp atmosphere pins decay much more rapidly than 
in a dry one. 
My attention was attracted to this subject twenty years or 
more ago. I have since then made some observations and 
experiments bearing on the subject, and I have come to the con- 
clusion that all insects of small size intended for permanent 
preservation should either be enclosed in cells, or fastened by a 
cum to card, or pierced with a silver-wire instead of a pin, the 
silver-wire being afterwards placed on a block carried by a thick 
strong pin. 
I have been in the habit of making my silver-wire pins my- 
self; but this was always difficult and unsatisfactory, and cost 
me a great deal of time. And I am accordingly glad to announce 
that Messrs. Watkins & Doncaster have succeeded in getting 
made a series of wire pins, of suitable sizes for small insects, from 
pure silver-wire, and that can be retailed at the moderate price 
of 6/- or 7/- per 1000. The sizes and thicknesses I suggested to 
them are: 1, 10 mm. long, and as fine as the minutien-nadeln 
made in Vienna, that is, much finer than Kirby & Beard’s 
No. 19 pin; 2, 12 mm. long, thickness of Kirby & Beard’s No. 19 
pin; 3, 14 mm. long, the thickness of Kirby & Beard’s No. 15 
pin; 4, 15 mm. long, thickness of Kirby & Beard’s No. 10 pin. 
These silver-wire pins, as supplied by Messrs. Watkins & Don- 
caster, are quite satisfactory, and from my experience of fifteen 
years or more I strongly recommend entomologists to use them, 
though a guarantee as to the pins being made of pure silver-wire 
must be understood to be necessary. 
The pin recommended by Mr. South is, 1 understand, made 
G 2 
