86 
HOW TO COLLECT 
As soon as the insects are quite dead they should be turned out on 
to a sheet of cork-carpet ; they should be touched as little as possible, 
the manipulations necessary to arranging the wings and legs being 
performed with a needle. 
When travelling, and time and space are of importance, mosquitoes 
need not be pinned, but may be collected in pill-boxes and kept firm 
by medicated cotton-wool. Glass-top boxes of metal are best for 
tropical climates. The gnats should be placed, when killed, on the 
glass, and then a loose plug of medicated cotton-wool placed on them, 
so as to prevent them from shaking about. 
To Pin a Mosquito. 
Take a card disc (b), and write on its underside the data connected 
with the specimen to be pinned, such as (1) name of locality, 
including altitude if necessary; (2) date — day, month, year — thus, 
9. 11. 98; (3) collector 's name; (4) any remark of interest, e.g. 
" Most troublesome species in district," or attach these remarks 
to the label (c). Place the disc on a sheet of cork-carpet, and 
make a tine puncture with a stout pin ; then pick up one of the 
fine No. 20 pins (d), and thrust about one-third of an inch of it 
through the puncture made in the disc (5). Lay the specimen on its 
back (turning it over with the aid of a needle), and thrust the pin, 
which now carries the disc, through the centre of the thorax, between 
more than its bulk of dry plaster of Paris ; cover this mixture with a layer of 
dry plaster of Paris to the depth of a quarter of an inch or so, and pour in 
above the whole a layer, half an inch in depth, consisting of plaster of Paris 
mixed with water to the consistency of cream. As soon as the top layer of 
plaster is dry the jar is ready for use. To obviate the risk of cracking the jar 
owing to the heat evolved when plaster of Paris is mixed with water, it may 
be advisable to stand the jar in warm water before adding the final layer. 
The exact amount of cyanide of potassium to be used is of no great con- 
sequence, but in the case of a properly prepared jar the odour should be 
readily perceptible on removing the lid ; if it is not, the reason may be that 
the mixture is too dry, when a little water poured on to the top layer will 
probably set matters right. After some months' use the cyanide loses its 
efficacy (to obviate this so far as possible the jar should never be allowed to 
remain open), and the mixture must then be renewed. 
