MOSQUITOES (CULICIDJi). 
87 
the bases of the legs, until the tip of the 
pin projects a little beyond the dorsal 
surface of the thorax* (e) ; invert the disc, 
and thrust an ordinary pin (a) through the 
disc near the margin for the purpose of 
carrying both disc and specimen. The next 
and last: thing to be done is to arrange the 
J h c legs and wings as far as possible — i.e. the 
wings must be made to project at an angle 
from the body, and not allowed to remain 
closed, and the legs must be disposed sym- 
metrically on the card disc. These operations 
must be performed as gently as possible with 
the help of a needle mounted in a handle, and care must be taken 
that hairs and scales are not rubbed off in the process. Proceed in 
much the same way in pinning specimens to show the ventral and 
lateral surfaces. The insect in the above figure is incorrectly drawn 
with the head towards the pin. This position should be reversed. 
Preservation of Larvae and Pup,e. 
Specimens of larvae and pupa? should always be preserved, especially 
when it is possible to breed some of them out, or otherwise to 
determine the species to which they belong. They should be killed 
and kept in alcohol or formol.f If in alcohol, it should be about 
60 per cent, strength. 
Of formol a 4 per cent, solution (i.e. one part of ordinary com- 
mercial 40 per cent, solution to nine parts of water) is quite strong 
enough for killing and preserving. 
Larvse and pupae (whether preserved in formol or alcohol) should 
* Should it be found impracticable to proceed in the manner here prescribed 
owing to the difficulty of making the specimen lie in the required position on 
its back, it may be pinned in the ordinary way through the middle of the 
thorax from the dorsal side ; in this case, however, the specimen must be 
pinned first (i.e. before it is mounted on the card disc) ; it should be drawn two- 
thirds of the way up the pin, and the latter should then be thrust through the 
disc, holding the pin with the forceps below the specimen; mount the disc on 
a common pin, as in the first method. 
f Otherwise known as formaldehyde or formalin. 
