87 
MOSQUITOES ( CULTCIBJE ). 
and thrust the pin, which now carries the disc, through the centre 
of the thorax, between the bases of the legs, 
d until the tip of the pin projects a little 
beyond the dorsal surface of the thorax* 
(cl) ; invert the disc, and thrust a No. 16 or 
an ordinary pin (e) 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 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 symmetrically on the 
card disc. These operations must be per¬ 
formed 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. 
Preservation of Larwe and Pup^e. 
Specimens of larvae and pupte 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. 
Larval 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 long pin, as in the first method. 
f Otherwise known as formaldehjde or formalin. 
