W. M. GRAHAM—THE PHOTOGRAPHY OF DIPTERA. 155 
THE PREPARATION OF THE INSECTS. 
Insects to be photographed are best killed in a cyanide bottle, for not being 
rendered so stiff as those killed by chloroform vapour, they are more readily set, 
and require less handling. The most satisfactory preparations are those made 
from insects mounted immediately after being killed. Fairly satisfactory prepara- 
tions can be made from dried unmounted specimens that have been thoroughly 
softened and relaxed by being placed upon damp sand in a closed vessel for a 
couple of days, but they require very much more skillful treatment than do 
freshly killed specimens. 
Take a pin of suitable size (No. 20 for small, No. 7 for large Diptera), cut off 
the head and sharpen the cut end. Then take a suitable dise of 3-ply Bristol 
board and push the pin through the centre of the disc. Lay the dead insect upon 
its back upon a sheet of smooth paper and carefully insert the pomt of the pin 
into the thorax in the median line vertically and in such a position between the 
fore and mid coxae that the subsequent setting of the legs will not be obstructed. 
The pin is then kept perpendicular to the surface and carefully pushed into the 
insect until it touches the chitinous covering of the upper surface of the thorax, 
but it must not penetrate or mark this surface in any way. Care must be taken 
to insert the pin vertically and not to move the insect about upon the paper, as 
by so doing the surface of the thorax in contact with the paper would be denuded. 
The disc with the insect now pinned upon it is raised from the table by means 
of the portion of the pin projecting from the cardboard, and the pin is gently 
drawn through the disc until the legs of the insect are in contact with the card- 
board. The nearer the insect is drawn to the disc the easier will be the 
subsequent focussing, as the legs and body will be set more nearly in the same 
plane and less depth of focus will be required. If drawn too close the position 
of the legs will be unnatural and the effect bad. With each increase of 
magnification this becomes a more important matter. 
Now lay the edge of the disc upon a sheet of cork and push a longer and 
stouter pin through the card near its periphery. The preparation 1s now mounted 
as a mosquito should be, and is fixed by means of the stout pin on a broad cork 
setting-board. Some minutes after its insertion the pin in the thorax becomes 
fixed by the drying of the exudation round it, and the further setting can be 
proceeded with. The wings are now gently and equally extended and retained 
in this position by being passed through loops of thick notepaper raised on pins 
to the height of the base of the wing. The legs are placed in a natural position 
and so as to display their distinctive marks, being retained’ in position by slips of 
thick note-paper or pins; and lastly, the position of the head and antenne is 
corrected if necessary. The board with the insect upon it should be protected 
against the attack of ants, &c., by being placed in a creosoted box, and should be 
inspected daily so that readjustments, rendered necessary by the drying, may be 
effected while still possible. The insect should be allowed to dry sufficiently for 
both wings and legs to retain their positions after the paper supports haye been 
removed. This usually requires some days, but photographing should not be too 
long delayed as the distortion and change of colour, induced by drying, may set 
in early and damage the specimen for picture-making. 
